Asymmetrical braking

[Nuckollsr]

1987 GMC R1500 RWD. Went through the brakes 95% about three years ago. Replaced/refurbished everything except hoses and master cylinder. Began to notice that left front wheel would slide with even moderate braking on wet pavement or loose dirt. Not a big deal normally but this caused me no nearly swap ends in traffic on wet pavement. After a change of underwear, I replace BOTH front calipers. No change. Took to local shop where they changed hoses, adjusted rear brakes and 'tested' on the paved parking and could not duplicate the event. However, the condition persists for moderate to heavy breaking on compromised surfaces. The only thing I have not replaced is master cylinder (can't imagine that's the problem) and the front disks . . . and oh yeah . . . front pads again.

Could it be that the friction coefficient of the left disk/pad combination is substantially higher than the other? I already changed the pair of calipers but didn't change the pads. I suppose that's next? Any ideas?

 

[Goldie Driver]

Sounds similar to Goldie where I assume the fronts (plural) are locking before the rears although I know the front DS is as I hear it with the window down.

I suspect the prop valve and have her in the shop to have that done.

Will advise on the outcome.

Hopefully the Chinesium prop valve works - it's all I can find.

 

[Bennyt]

You are talking about two different problems, a r/l bias issue and front/rear issue.

If you really want to diagnose the L/R issue...You need to check caliper pressure with gauges to see where the issue is. They are a block that goes between the pads with a gauge and you have a helper press the brake and it tells how much squeeze the caliper has. If they are the same left to right you know it's not a hydraulic issue and you can move onto mechanical aspects such as bearing, slides/pins/bushings, rotor/pad.

Doubtful a prop valve will fix a l/r issue but could correct f/r.

 

[Bennyt]

Does it pull when braking?

 

[Goldie Driver]

FYI-

Prop valve may have helped the issue but not completely solved it on Goldie.

The test patch I use is a piece of rough concrete heading South on the 59 feeder street at West Airport going for the uturn lane that leads to the North 59 feeder and entrance ramp.

It is almost always wet and is slippier than owl sh!t .

The 4RUNNER, with 4 wheel antilock, will activate in this spot.

Post prop valve I can still hear the front lock up.

Overall braking is improved although there is a "2 toned effect" and I think you feel in the pedal the handoff from rear to front/all braking.

Chinesium PV2 valve from Amazon for full disclosure.