1999 Tahoe, soft brake pedal

[99brokeTahoe]

My apologies if this problem has been addressed in another thread, I could find some close, but not the same. 1999 Tahoe, original problem was brake pedal would intermittently feel "notchy", like the ABS was actuating, but I know what that feels like, and this isn't it. Truck has 290,*** miles, and I have replaced a lot parts, but not a brake MC. Replaced MC with a NAPA MC, bled all 4 corners till the fluid looked good coming out, did the "dirt road ABS bleed procedure". Brake pedal felt better than it ever had, but problem with pedal feeling like it was binding, or hanging up, would still happen intermittently. So I replaced the booster with a NAPA booster. To me, brakes feel worse than they ever have. I'm not an engineer, but it's like the return spring in the booster is too strong, so you can't make the pedal move as fast down, but it has enough assist to go to the floor. Truck has almost everything new in the last year or 2, and the aftermarket booster has made the pedal feel soft to me. Truck will lock the wheels, and make the ABS work, but you can't do it as fast now, than you could have with the original booster. Guess I need to try a different brand booster? Any suggestions?

 

[Matahoe]

Binding, chattering or resistance when pressing the brake pedal would either be the linkage from the pedal to the MC or the MC itself. The vacuum booster is easy to rule out. Just disconnect and block off the hose at the booster and see if pedal travel feels any better, worse or same when taken for a drive. Just be aware you will need a heavy foot and increased distance between you and any object in front. Gonna take longer to stop. Brake pedal travel should feel the same with or without booster. This should get you pointed in the right direction. There is a recall TSB related to the brake rod retainer but not sure if that involves how the brake pedal feels.

 

[rockola1971]

Did you get the little rod that goes into the brake booster out of the old one and install into your new one? Is your brake light coming on? I suspect you still have some air trapped at your ABS manifold because you didnt use an auto bleed feature of a bidirectional scanner. Seen this scenario right her on this forum so many times.

 

[99brokeTahoe]

Did you get the little rod that goes into the brake booster out of the old one and install into your new one? Is your brake light coming on? I suspect you still have some air trapped at your ABS manifold because you didnt use an auto bleed feature of a bidirectional scanner. Seen this scenario right her on this forum so many times.

I have a Chinese Tech2, and I'll try service bled procedure. I have always had good experience with just making the ABS work on loose gravel road. Before I installed the new booster, I looked at both side by side, expecting an adjustable push rod, but didn't see that, and I didn't notice anything different between the 2. If there was a rid extension on the old booster, I didn't notice it. Brake pedal felt good till I changed the booster. I didn't open the hydraulic side of the system to change the booster. I think I just got a bad/wrong booster, or maybe I missed an extension rod on the end of the old booster. I have a 1997 Tahoe parts truck that I'm going to try and swap boosters with. It just seems like a lot of work for a used part, and maybe my expectations were to high for my NAPA part. Before I do anything, I will try the bleed procedure with my scan tool. Frustrated, and was hoping to find a "magic silver bullet", so to speak here. I've had a few of these trucks before, and worked on a lot more, and never had this much trouble.

 

[99brokeTahoe]

Oh, and thank you for all the replies.

 

[99brokeTahoe]

Also, new member. Just joined. Haven't been on any forums in a while, but used to read them just to learn. The tech threads on here seem to be a lot more "right" than the Facebook groups. Anyway, seems like a lot of good knowledge on this forum.

 

[99brokeTahoe]

 

[rockola1971]

Also, new member. Just joined. Haven't been on any forums in a while, but used to read them just to learn. The tech threads on here seem to be a lot more "right" than the Facebook groups. Anyway, seems like a lot of good knowledge on this forum.

Theres a very good collection of good guys on here with everything from super freaks who stick 6.0's with goodies mounted on the engine in place of their tired 5.3L, transmission rebuilders (for a living) to guys that have owned or do own repair shops. Its all here and everything in between. I also have the clone Tech II. I always use the bleed feature on it. Its never done me wrong.

 

[Matahoe]

I have a Chinese Tech2, and I'll try service bled procedure. I have always had good experience with just making the ABS work on loose gravel road.

You can do that but either way you will need to bleed the lines again after driving. Maybe 2 or 3 times. The automated bleed just lets you do it in the shop so you're not having to drive then bleed repeatedly.

 

[Eman85]

Best fix I found on OBS trucks is to use a NBS MC, makes the pedal feel like you're actually going to stop. I must just be lucky but I've never had any problem bleeding these brake systems and I do have a scan tool that can do the ABS activation but never see any difference if I do it that way or without.
Test on a booster is to pump the pedal multiple times with the truck off. Then while holding pressure on the pedal start the truck and you will feel if the booster is working as the pedal will drop.
The simple test on a MC is buy 2 plugs for the MC, thread them in and step on the pedal. This will let you know if you have air in the MC or just how high the pedal can be if the system is good. Of course every wheel's brakes should be inspected and all of the lines especially on a 25yo truck.