Touchy Brakes

[TwistedTahoe]

I've got a 99 Tahoe LT 4wd 4dr with 4 wheel antilock brakes (currently not working).
When I press the brake pedal, nothing happens until the very end when the brakes grab violently. At low speeds my passenger rear wheel locks up.
I went on Identifix and they say it's either a BPMV (Brake Pressure Monitoring Valve) or the master cylinder itself. I was wondering if any of you knew how to test either of these, or could offer some guidance.

 

[454cid]

Assuming when you say nothing happens, you mean nothing odd happens...

Passenger wheel.... front? Rear? The anti-lock system provides proportioning front/rear on out trucks. Having it disabled on my truck makes my rears lock up. It could be that one side is a bit more worn on your truck, or you could have multiple issues.

 

[Pinger]

I had the long pedal and sharp brakes toward the far end of the pedal travel. Bleeding improved matters.
I replaced a master cylinder, rear cylinders (leaking), and all flexible hoses but it was the bleeding that made the difference.

 

[Donald Mitchell]

"At low speeds my passenger rear wheel locks up." Look and see if the wheel cylinder is leaking

 

[Supercharged111]

"At low speeds my passenger rear wheel locks up." Look and see if the wheel cylinder is leaking

I was thinking this and rears out of adjustment.

 

[Schurkey]

I've got a 99 Tahoe LT 4wd 4dr with 4 wheel antilock brakes (currently not working).
When I press the brake pedal, nothing happens until the very end when the brakes grab violently. At low speeds my passenger rear wheel locks up.
I went on Identifix and they say it's either a BPMV (Brake Pressure Monitoring Valve) or the master cylinder itself. I was wondering if any of you knew how to test either of these, or could offer some guidance.

Perhaps a moderator will move this thread to Axles + Brakes.

Hateful, piece-of-crap 254mm leading/trailing shoe rear brakes? Grossly out of adjustment because you never use the park brake? Or do the Tahoes get the decent, 11.x Duo Servo rear brakes?

Shoes contaminated from wheel cylinder or axle seal leaks?

Start taking things apart for cleaning, inspection, adjustment/repair.

Bleeding (really, flushing) the old brake fluid is a great idea once all the hydraulic system is inspected and in good order. You'll need a scan tool.

 

[Dariusz Salomon]

I don't suppose that's it but when my rear brake shoes disintegrated(chunks detached) I had really grabby rear brakes-as in the truck would just lock the wheels. So as Schurkey said earlier-I'd drop that drums and see what's inside

 

[Nad_Yvalhosert]

Perhaps a moderator will move this thread to Axles + Brakes.

Hateful, piece-of-crap 254mm leading/trailing shoe rear brakes? Grossly out of adjustment because you never use the park brake? Or do the Tahoes get the decent, 11.x Duo Servo rear brakes?

Shoes contaminated from wheel cylinder or axle seal leaks?

Start taking things apart for cleaning, inspection, adjustment/repair.

Bleeding (really, flushing) the old brake fluid is a great idea once all the hydraulic system is inspected and in good order. You'll need a scan tool.

As far as I have seen, the terrible leading/trailing shoes are relegated to pickups. SUV's got the better ones.

Of course there might be a unicorn out there, but I've never seen it.

 

[TwistedTahoe]

Perhaps a moderator will move this thread to Axles + Brakes.

Hateful, piece-of-crap 254mm leading/trailing shoe rear brakes? Grossly out of adjustment because you never use the park brake? Or do the Tahoes get the decent, 11.x Duo Servo rear brakes?

Shoes contaminated from wheel cylinder or axle seal leaks?

Start taking things apart for cleaning, inspection, adjustment/repair.

Bleeding (really, flushing) the old brake fluid is a great idea once all the hydraulic system is inspected and in good order. You'll need a scan tool.

Sorry for the long response. After thinking about it I adjusted the rear drums (they were both crazy out) and bled the abs (because I jumped the gun on the Master Cylinder) I have a brand new pedal! Some idiot re-welded the backing plate holes shut so you can imagine the frustration.