Braking issue

[selahpartners]

2001 Chevy Tahoe, 374,000 mi... intermittently having issues of when braking, especially firm braking when you need to depend on it, it starts braking as normal, but then the pedal softens and moves closer to the floor... I had the system flushed with new fluid and bled... still the same issue. To me the next move is a new master cylinder?? Any thoughts?

 

[Fless]

Does it have the vacuum boost, or the hydroboost system?

 

[selahpartners]

I have no idea... is it easy to tell? It does have a big "container" behind the plastic master cylinder reservoir.

 

[selahpartners]

Does it have the vacuum boost, or the hydroboost system?

I just looked it up and it is Hydraboost

 

[selahpartners]

Does it have the vacuum boost, or the hydroboost system?

after viewing a hydroboost on the web... I must have the old school vaccuum booster... but the web told me that a 2001 Tahoe would have Hydroboost... but evidently I do not

 

[rockola1971]

Hydraboost is fed power steering fluid from the power steering pump via hoses. Vac booster is big round pillow made of metal that your master bolts directly to.

You could have the master going bad and if it is the culprit, then one day you push on the brakes and it will go straight to the floor and NO BRAKING action. I suspect the master or collapsing rubber brake hoses going to the calipers. First inspect all inside of wheels for evidence of leaking brake fluid. Is your brake light coming on at all? Has your ABS been throwing codes?

 

[grouch]

2001 Chevy Tahoe, 374,000 mi... intermittently having issues of when braking, especially firm braking when you need to depend on it, it starts braking as normal, but then the pedal softens and moves closer to the floor... I had the system flushed with new fluid and bled... still the same issue. To me the next move is a new master cylinder?? Any thoughts?

That is text book master cylinder failure. One of the cups inside has failed. The others are not far behind. Especially with fresh fluid. I'll bet you can have the engine running and press HARD and the pedal might begin to sink.

I'm not a fan of throwing parts at a problem but this one is pretty clear cut. Especially if it's the factory master cylinder. 24 years and nearly 400K. It is at the end of its service life. Well past it actually.

 

[N3six]

Mine was doing the same thing, I knew it wasn't the the brakes or abs (new calipers all round and new wheel Barings to fix the abs light and code being thrown) turns out the master was going bad so I went to the salvage yard and plucked an oem one flushed it and that solved my problems.

 

[rockola1971]

Mine was doing the same thing, I knew it wasn't the the brakes or abs (new calipers all round and new wheel Barings to fix the abs light and code being thrown) turns out the master was going bad so I went to the salvage yard and plucked an oem one flushed it and that solved my problems.

Getting a master cylinder from the salvage yard is CRAZY!