Hello everybody, Good day to you and welcome back! Glad you guys are here! I know I'm super glad to be here. This is a 2004 Chevrolet Suburban is a 1500 Suburban that's the six lug with a 5.3 L V8 that's the Oo. customer states that when starting the vehicle, the brake pedal pops up and runs into his foot and on occasion when he goes to uh, apply the brakes while driving, the brake pedal will bounce back in forth, up and down quite rapidly. uh which causes some alarm and we're going to go ahead and take a look and see what's going on with this uh hydraulic braking system.

So stay tuned because this is going to be a very good video upy Hood look who that guy is key on. let's apply the brake. look at that straight to the floor beginning engine starting sequence now. Okay, you guys saw that jolt that it did when we uh started up the engine.

So as soon as this thing came, uh into some kind of a break assist mode whether it be I I think this actually has a Hydro Boost uh but as soon as the power steering pump or the brake booster began to apply assistance to the pedal, we saw that uh, that jar and the thing pop back up and that's uh, exactly uh as how the uh the condition was described while driving is, occasionally the customer would hit the brakes and it would get this rapid pedal feed back uh from the pedal assembly and it's quite alarming and uncomfortable while driving. So we're going to take a look into that right now. Let's go ahead, get this thing into gear. Let's get it out of our parking space.

Uh, I'm thinking one quick test drive around the block, up and over the bridge just to see how the service brakes feel on this, to make sure we don't have to do anything additional and then we'll swing this unit into the shop and popsy. Hood Take a look at the Uh brake boosting system and see what's going on and we're off. Smooth accelerator All right. Our first brake event: applying the pedal and it feels fairly normal while driving.

Brake assist feels fairly normal. Like I said, it's It's an occasional and an intermittent uh. we did see the Uh symptom appear straight away, but I'd like to recreate it once while driving just to see what happens here, see if we can do it on another stop up here at this upcoming Red Lay accelerometer and applying some brakes. We're going to do rapid pedal actuation.

Watch this. I Kind of felt some Vibe or a little bit of feedback, but it didn't appear to be, uh, anything dramatic. Let's go up and over the bridge once we'll try a couple more stops in the way down and then we're swinging back into the shop. I Believe what we have is an issue with the brake booster system.

Now this truck feels like it's a, uh, a hydroboost. Hello Shop! It feels like it's a Hydr boost. That means it gets its power brake assist from the power steering system and it does not have a vacuum booster most Vehicles just have a vacuum diaphragm uh inside of a container that is connected to the engine intake manifold vacuum. Uh, this particular setup based on kind of what it feels like does not have a vacuum brake booster.

I Believe it has a power steering assisted brake booster which is the same thing it just uses. uh like I said, it uses power steering pump pressure uh for the assist Force rather than engine vacuum. And while I was rambling on, we came to a complete stop and again I did not feel any feedback from this pedal. uh, this time around green light.

so we're going to head up to that next light and we'll see if we can't generate some feedback on the pedal. I'll get you guys down here for a decent view on what we're looking at. Here it comes braking n that was a nice smooth brake event. Okay, other than that, we have a fairly decent pedal.

It actuates quickly. We have actuation right here. so the braking system or the hydraulic SL Service brake system appears to be doing what it's supposed to be doing. Uh, therefore my calculates we have an issue with the booster.

Oh no, we're going to catch the train. See the lights up there? Oh I Just felt some more feedback in that pedal. Look at this guy right here. Hang on.

Hang on stupid. You're on the wrong side of the road for backing up. You know these guys are going to pull up. They're going to switch out a train car and they're going to back right in.

and then this guy right here will still be at the light back there trying to circumvent the Train by going up and over the bridge and around when they could have just waited for a second cuz they're not going to block this for for very long. I Yeah, look, it's a 1, 2, 3, 4. Oh I can't see it's an 8 car train. Maybe 42 seconds later and that's the end of the train.

Yeah, all righty. pulling back into the shop at 2,778 Mi on the odometer. let's take a look. We're going to nose this thing in.

We're going to pop the hood. We're going to take a look, uh, at the brake booster system, see if we cannot find any other perhaps visual identifiers of an issue. Uh, maybe there's some leaks or something broken things of that nature. So let's take a peek at the brake booster system and then we'll make a judgment call from there on what.

uh, what needs to be done. Maybe fluid's just low? Who knows. Parking is the auto. We're going to leave it running because if we have leaks I want to be able to see them, Let's hop on out of here repping.

Z Hood All right. Moving around to the front here, let's get this. Bonnet opened. Hello! 5.3 L V8 The Ultr.

Okay, moving into our brake assist area, we have our brake master cylinder reservoir right here. That's what holds all the extra fluid. This uh, silver component that's the master cylinder that connects to the output line. uh for the front brakes and the rear brakes.

Uh, these run down to the ABS module back through the firewall. We have the brake lever and then the brake lever. Rod That Rod is going to actuate a plunger on this hydroboost unit right here. And like I mentioned earlier, this thing receives power steering line pressure through these.

uh, one of these two hoses that runs down to the power steering pump right down there below, which is engine driven. So it takes mechanical engine driven, converts it into hydraulic energy, and then that hydraulic energy is harnessed and used to assist the driver in actuating the brake pedal. And from what I'm looking at here, I See a little bit of fluid saturation going on on that accumulator tube right there? Uh, it's indicative of maybe a small leak. Uh, a lot of times though, these things tend to leak at the seal between the brake booster uh and the brake master cylinder.

Um, really, no major evidence that that, but kind of based on everything that we have experienced or that I' I've experienced so far. you guys didn't feel it but I did so based on everything I felt and experienced uh plus some past knowledge I Do believe we have a faulty accumulator piston uh inside of this uh, brake Master cylinder or or hydroboost rather. So what I'm going to do is recommend a remanufactured replacement for that unit and that will prevent those symptoms from reoccurring. Okay I don't think we need the engine running anymore.

Hug power this unit down. We're going to open and close the door so all the electronical inside shut off and we don't kill the battery. We are now shut down. Um what I think I'd like to do before I fully condemn this master or this.

Hydro Boost rather is we're going to use 2 15 mm sockets, pull off these nuts right here and we're going to separate the master cylinder from the booster. I Want to check for a leak? uh back there behind that unit? All right. 15 Extension: Wobble on the electron ratchet coming in. We're just going to break these two nuts loose on this uh master cylinder and walk this thing back.

Now we're not gravit toss as I was saying. Well, what we're not going to do is disconnect the Uh brake system lines from the master cylinder. There's no need to break into the hydraulic system. Uh, uh.

regarding the service, Brak We can do this without getting into that system. so we're going to reach back behind those lines. We're going to get a hold of the second Fastener and again. crack that guy loose, Spin the nut right on out.

Oh, that one's not working. It was unthreading the stud at the same time. These boosters also have a stud on the other side of them, and if you go to remove the nut, it's actually turning in the same direction as the reverse threads on the stud and it can cause the stud to back out. If that happens, and you're trying to service it, you just put a wrench, uh, on that stud right there and hold that thing still.

and then you can get your nuts off without, uh, too much difficulty. So that one worked out cuz it. the nut came off even though the stud became disconnected. And look at that right there.

That's a little groy that's nasty. Yeah, yeah. look at that bunch of rust and buildup. Definitely a leaker.

So we do have a confirmed issue with this Hydr boost unit. I'm going to go ahead and get one ordered. We're going to replace this thing. Uh, ASAP That's not okay.

All righty. I Think we are good to proceed. I Have ordered a replacement component. Let's go ahead and get started with some disassembly.

We're going to crack the two lines, loose the pressure lines, and then we're also going to remove this, uh, return line right here. That's the one that goes back to the reservoir. So let's get these guys broken loose right here. Couple open-ended wrenches.

we'll do do the trick. We've got a 18 and then I think that other one is a 16 on the back side here. So real simple and easy to do. Crack them loose, unthread them, pull the fitting back, spill some fluid.

There we go. That's all power steering. that's nasty. That's nasty fluid.

Just let that hang out right there. I've got a drain pan down below folks. No worries. all this gets cleaned up.

After words. That's just part of the gig. Unclick That's our 16 fitting. It's actually around behind this.

uh, return line right here. I Tell you what. I'm going to pull this return line off and make it a little bit easier to reach everything. So here what I can do is we'll unclamp the clamp and clamp it more and just give it some wiggle action as we pull upward.

and that's going to remove this line from the the fitting there sticking out of the booster. Come on, get out of there. there we go. Hang that up and this thing can also be disconnected and that's going to give us some wrench space.

So let's get a hold of this nipple right here. Give it a Twist Didn't take much and a couple more twist here. Ow no hope I don't need that I heard it hit the ground I Know where it is. Grab it in a moment.

Anyway, let's pull this 16 fitting off and that will completely disconnect this booster unit from the hydraulic system. Come on. Nope, that one's a little stiff. There we go, that fittings off.

We'll pop this guy out. Just kind of set that aside. so everything has been disconnected from this booster unit. Now we need to get into the cabin, go down below the driver's foot well, and we're going to find that there are four studs.

one two, and then there's number three. Number four is back there somewhere. There's four studs going through the firewall. We need to get the nuts off of those studs and then we can extract this unit through the engine compartment side of the firewall.

Okay, reentering the auto. Let's go ahead and slide our seat back some. We're looking for the section down here where our boosting unit comes through. Oh, look.

another flaw. flaw. fault fault flaw you see right there on that. Uh, let me point at it.

See right there. a little shaft coming through. You can see that that thing's highly saturated uh with some oil. So that tells me this unit is leaking from the back side as well.

See that right there. So we have two uh, confirmed failures uh on this booster unit right here. so that's good. That makes me feel better about replacing it cuz those things are not cheap.

Okie Do so I've got you guys sitting on top of the brake pet. p lever. Uh, what we're looking at right here is the electronic connector for the brake pedal and cruise control switch and right there that is the rod. I Don't even think you can see that.

that's the rod right there for the brake booster. Okay, so what we need to be doing here is getting this connector disconnected and then we have to separate the rod. Ah, there's our connection connect door and my light fell. We need to separate the rod from the brake pedal itself and we'll need to do that by removing the switch, which is what we're looking at here.

That's the brake pedal switch and we have to remove this clip right here in order to remove the switch. Now, this is a kind of a compound clip. There's a a keyway here that hangs onto this stud and then this clip will wrap around the stud and then it hooks again on the back side. Uh, creating a level of redundancy to prevent this system from coming apart while driving Because if this Rod comes off of this, uh, this brake pedal lever right here, the operator will no longer have the ability to apply the service brakes and that would be bad.

So what I'm trying to do here is get this pocket screwdriver behind it and pry out that, uh, that clip right here. These easier said than done There we go. and then I can take this clip and drop it on the floor. No worries.

I Got it there. She is right there. See how it's uh, got this keyway in it? Let me get you some better light here. see how it has this keyway? so it's got the larger diameter hole here to fit over that? Peg And then as it clicks over, this section of the clip will clip onto the back side of the peg, preventing this unit from coming off.

So now that we have that thing disengaged, we can reach up and pull the switch and the rod off of the lever. It's right there. Let me try to do this and maintain some illumination so they're now separated. Here Comes Our switch gravitas there with me, folks.

So that's our switch right there that slips over the Peg and inside of those two flaps on that switch or tabs. Rather, it encompasses the area for the lever coming through the firewall. See how that works? It's got that hole in it there and then that will slip over that Peg The brake pedal switch slips over the peg as well and then the Clip Clips onto that Groove and then around the peg EG and that secures everything to the pedal assembly. So now that that is disconnected, we've got one, two, and then what's those other ones? Three and four somewhere? There's four 15 mm nuts attached to the studs coming through the firewall.

We need to disconnect those four nuts and then that whole unit will come out of the firewall. So let me get out of here. we go fetch a tool and get back into our dungeon. All right, going back in.

Got a 15 mm deep well socket on a universal wobbly bit with an extension on the Milwaukee 3/8 stubby electron impact. So what we're going to do is we're going to let our flashlight die. either died or I' turn it off by mistake I think I turned it off. Anyway, we're going to get our dangly wobbly bit up on our hardest to reach.

Fasteners First that right there. give that some reverse click and that is one I think that's one of the nuts there Yer Okay, we got one of those guys disconnected. Let's reach in there and pull the nut out. Oh, that's tight squeeze for me.

Okay, that's one. I'd like to get the other one up at the top first, but that's that's. kind of hard to do. a little bit hard to do.

You guys see what I'm up to here. The nut is a little bit higher up. uhoh I'm stuck. Hang on here.

Let's take our gun off. pull the lever up some. The brake pedal lever is in the way. There we go now.

I can get that guy up there I Think here. it took a a little bit of arranging, but I managed to get the uh, the socket and extension through that little narrow. Hole uh again I Know you guys can't see very well. It's close quarters combat.

We're going to try to get that nut out. Unclick Here it comes. That's the hardest one to reach cuz it's way way in there. But we got it out mostly.

ow P my finger come on nut. There it is. Got it! Woo! Okay, so those are the top ones. The next one's a bit easier.

It's farther down and at a better angle of attack so to speak. See this: Pull that one out, reaching back to fetch it I don't want to leave them there cuz if they fall, they can roll behind the carpet. they'll roll behind the carpet. Then they'll get stuck.

and I don't want to peel the carpet back. Okay Uno Moss Right there. That's number four. That's our last one.

Let's recover that guy. Now we're done down here for the time being. Let's go back into the engine compartment and then we can extract that booster assembly from the firewall. Woo! Okay, so we're going to pull this master cylinder kind of out of the way as far as possible here, which is not very much farther than where we had it, unfortunately, and we can just just kind of a tug and pull those studs through the firewall there, Taking the shaft with it and our hydr boost unit has been removed.

All right. The parts house has showed up with a container that contains nonflammable gases. I Do believe this is my unit. It's a GM Part number Uh, number 1 Niner 3 71355 that's the GM number I Do believe this is the right one.

the picture said it was. let's get this thing opened up and see what we have inside. Lot of packing material we have that got some paper. Got some cardboard? I see some shiny metal? I see another nipple? It just sprayed at us? All right we put that back.

Okay I Do believe this is definitely our booster unit. Let's dig this thing out of here and compare it with the old one. Let see what we get. Nice and shiny.

Warning: If Do Not remove this pedal rod from hydraulic booster pedal rod is not a serviceable part so we cannot take this thing off of this thing according to the destructions, let's take a look on our input side our output side Here we you can see that's the rod that actuates the Uh, the brake master cylinder and this little star thing in here that retains the spring and the rod which is what keeps that centered so we don't take that out. Some of these like the aftermarket ones, we have to remove that little clip and then pull the rod out of it and then swap that Rod into the new units. Uh, However, since this right here is a genuine GM part, we don't have to go through all that. Rigo So we'll bring this one over to the bench and compare the two just to make sure that, uh, we're looking at the right stuff.

here. We've got fitting fitting, fitting, fitting, nipple nipple fitting. We've got our Rod backing plate and four studs. Okay, this thing passes the test.

It visually appears to be identical. Little slight difference here. This one has a sight glass on it that and does not I think that's a sight glass? Uh. Regardless, other than those two slight differences, I Do believe this is a satisfactory unit.

So let's go ahead and get this thing prepped and set up in a position over here in the truck on the firewall. We'll slide it in BTT it in, connect it up, and then see how she feels here. We're going to stash that over to the side so it can't get hung up. That looks good, and we're just going to take this booster Slide the rod into the hole, maneuver everything past our obstructions.

Let's get it lined up here, and then we'll stick the studs in. There we go. and while we're here, we can go ahead and sandwich these other components together. Let's wipe this down a little bit.

Had some fluid built up on it. There we go so we can get all this stuff kind of in position for when we return to it after that booster is bolted into the firewall. All righty. Now that we have this thing mostly set up and in position, I'm going to throw a couple of nuts on there just so it can't fall apart again.

and looking back around the back side, we see that stud is now fully inserted. It's not backed away on this particular model. Put those studs in that looks good. The rest of the stuff we can deal with uh, after we get the four nuts tightened inside the firewall.

So we're going back down into the uh, cavernous and dungeoness footwell area and we're going to get all these bolts and stuff in position here. So here let's get. we'll get these guys started by hand and we'll go in with the wobbly 15. Finish them off, get the easy ones in first cuz we can reach those and then the harder ones.

Well, we'll just have to maneuver around some stuff, pull the brake lever up, reach on back, that's the bottom hard one and then the uh, the top one that not go. Top one's way up there. We can barely see it from here, but I can feel it. Okay, that top one's on now.

I'm going to attempt to tighten that hardest one first. That way it just gets easier as we go. As soon as I get this thing locked down, we'll we'll uh take care of the rod and the pedal. okay impact clicker coming in tight.

Let's get our lower left just so we can attempt to do this in some kind of a pattern here. Get out of the way transmission cable. come on. I Can't even reach back there.

There we go. Okay, that one's tight. We'll get the right rearer next and the upper left or left front. Rather, we'll call it the left front.

Kind of like their tires. All right. Good to go. That unit is bolted to the firewall.

Now we need to get the switch and that lever or a a rod rather installed. Rod Rather, that's what it is. let's install the rod rather all right. Reaching up in here again Close Quarters Combat Continuing, What we need to do is slide that Rod over the shaft like.

so wiggle that in until it's straight Orient it properly. Then our switch can also oh too much. Our slitch will switch will slide up and over and lock in, and then we slide it on the rest of the way to put the other ear of the switch over the rod. There we go.

Just like so. So now that switch is in position, we can come on in with our clip. I Know it's really tough to see folks. I'm sorry, but like I said, it's close quarters combat.

But we take that clip, push it over and expand it, and then slide it up so the keyway clicks over that little Groove that we saw in the rod on the pedal and I can't even see it. So I'm hoping that the uh, the audio here is enough to get us through. Oh man, that's tough too. You can't fit two hands up there.

just the one. wiggle it some, it'll snap when it's ready. There we go. Okay, that guy's on.

Give it some tugs, make sure it doesn't come out I Think we're good and we just need to plug in our connector. It's in good shape, all right. we're done. under the dash.

let's get out of here. it's getting a little warm house. Woo! All right, we're going to need to extract both of these plugs right here because these go back into the old unit so it doesn't leak cuz that gets sent back to the parts people as a core. So we'll plug that up with the these little connectors here.

that one there. that one got them in the wrong hole. It happens that one goes in there, that one's smaller, goes in a smaller hole, bigger one goes in a bigger hole. Okay, so now we can take this thing, toss it back in the Box We're done with this.

Goodbye Old unit coming on in with our 50 wobble Again, go ahead and tight down these bolts for the master. Cinder Get on there. Very good. Okay, so now that unit's bolted on, all that is left is I need to re o-ring the fittings, screw them on, tighten it down, fill it up with some oils and fluids, and then we will retest it all right.

O-ring kit coming in. not those. I'm thinking it's these little guys on the end here. let's grab one and see how they fit.

Okay, that's looking good. All right, that one goes there. Uno Moss for the other side I Believe they're the same size. unfor.

Fortunately, the uh, the unit did not come with a replacement o-ring You would need to get the Uh the actual hose in order to get the replacement o-ring and we didn't get the hose. we got the booster assembly. Anyway, that one has been screwed down. Let's get some torque on this fitting now.

nothing crazy. We don't want to break the housing, you just kind of kind of click it on. Put our return hose back on in position. H Get on there, Get that's position.

Very good. Now we just got that one. uh, one other pressure hose and we're good to go here. Let's see here.

Get that guy started. Always start him by hand, especially these hose fittings. You can get them sideways and they feel like they go in a couple threads and you start wrenching on them with your tool and they get a little tight but they still turn so you're like okay, so you wrench a little harder, then you wrench a little harder. Next you know you crack the case on uh, on your units and then damage it Beyond repair and then you got to buy another one.

So if it does not go in by hand, do not force it. That's how things get hurt. Clicks there we go. Okay, so now this unit is installed.

the brake master cylinder is installed, the new booster is installed, the brake pedal is connected, the brake switch is connected. What we need to do next is clear our goodies off the battlefield, refill some power steering fluid, restart the engine Purge the air out of it, which we just need to let it run for a while. Hit the brake a few times so we purge the air. We'll clean our mess and then take it on test drive.

What we need to do is hold our brake down on immediate startup and see if it gets that that bounce to it. Um, these Hydr boost systems are supposed to give you pedal feedback when you start them, but they're not supposed to be bouncing around and that was the uh the issue. uh regarding the complaint and I Need a funnel and some cleaning spray here. Get rid of all of our spillage.

Let it run down all nice. Like bu spillage of the fluids. it's just on top of ther Well, we're good. Clean off the Uh brake master while we're here.

Leave no fingerprints or evidence. Nice and shiny. Very nice. It's like it never happen.

Awesome! Oh no. I'm running out another there Okie Dos off to the Vault of viscos. Let me go ahead and fetch some Snake Oil Power Steering Fluid I Only say that because every time I have something that says BG on it which is the stuff that I use here. Uh, you guys go re re re and get mad at me for selling fake fluid I guess I don't know.

that's that's what the comments tell me here since we're not doing a complete fluid exchange and there is some fluid left over in there. I'll dump in a little bit of conditioner that's an additive package. It prevents foaming and it prevents noises and it prevents component breakdown and things of that nature. So now I've seem to fill up the remainder of the fluid and I hope I don't spill any.

Once that's refilled we can go ahead. Oh and I spilled it. Yep, that didn't work. Okay well Su some of that back out will be okay.

went too far. No matter, we'll throw the cap back on there. So I don't contaminate my system and we can also deoil what I just did. Okay, so what we're going to do.

Go to the cabin, Restart The engine power steering pump's going to come alive. It's going to pump all the air and whatnot out of this. and then we can recheck the level. Okay, beginning engine restocking sequence.

Now hey, that was uneventful. Full beans. Okay, let's go give it some brake pedal actuations. Hey Dave I Had the brake switch out of this.

Will you take a look at the lights and just make sure they come on? Just give me a yay or nay. uh. brakes brakes off? Okay, did you guys see my foot how it got that crazy? Kickback That was this thing purging air out of it. Okay, so now what we'll do is we'll shut her down and I'm going to give it some pedal actuation.

We're going to restart it. Ah, that was better. You see how it sunk and then just came back up when the engine started. That's what we wanted to see.

What we didn't want it to do was just kick back at us like it did on our first start. Do it one more time. Yep. I Felt some slight pressure come up and that is all.

good to go. It feels better. Let's go back. Recheck our fluid levels.

Go ahead, pull our cat back off and check. Our fluid level should have gone down considerably and it did. Cool beans. All right, that's in good shape, that's in good shape.

everything else is in good shape. Let's go for one more test drive to make sure we feel solid and then uh, this operation will be good to go. Let's get our Illuminator shut down. Get this thing out of the way.

We'll hang you back up on the wall. Get rid of that. Goodbye 5.3 L All righty. Parking brake light is on.

We had hit the lever disengaged parking brake. Let's go ahead and back her out. Honks for safety. Rack is cleared Dave's over there.

no one's in the shop. Good to go. All right. One more trip around the block and we are good to go here.

Uh, basically what I'm going to be looking for is any abnormal pedal feed feedback. uh which I don't expect to find but you never know. You've got to test out your new parts after you put them on just to make sure that they're going to work and that they're going to work reliably cuz you never want to give a car back to somebody without having proved out that what you had done had, uh, caused an effect or a change or an effectful change. Words all first stock while moving and no abnormal pedal feedback.

Excellent. Yep, a couple more of these and I'll be Satisfied and I can park this thing and move on to something else. So all that being said, gas can I Do not believe I have anything more to offer you in this particular video I have no more commentary I have no more repairs I have no more entertaining educational quirks uh for this particular episode. So as always like to thank each and every one of you guys for watching this video.

Certainly hope you enjoyed this video. If in fact, you did enjoy this video. Please feel free to let me know about that by tapping that like button down below. Do not forget to drop me a comment or two while down there and most importantly, have yourselves a fantastic day! See you guys later! Thank you for watching See you in the next one in a video into the Break Hydro Boost Brake booster into Chevy Suburban End of transmission.