Violent shudder and shaking

[xit]

OK boys and girls, I need some help. Here is what it is, big problem with my brakes, when barely moving, 1-2 miles per hour & I press the brakes to slow to a stop, I get a violent shudder that shakes the entire van, just so harsh and shaking. This does not happen all the time, just random, especially on a slight downward incline when stopping slowly.
I thought it might be the pads so I installed new ceramic pads and packed the wheel bearings, used the grease that came with the pads as instructed, all looked good no movement or wear & the bearings looked like new as did the rotors.
I am at a loss, may be the wheel brake clyinders, master cylinder, rotors, rubber brake lines, I don't know where to begin, any help appreciated. BTW brakes are fine otherwise, no other problems.

[sixsix]

ABS circuitry, flaky fuse, breaker? - wish I could help more...



Mike

[Astrofarian]

This one may be difficult at best to diagnose remotely. My shot in the dark would be to check/lubricate the caliper slides up front and ensure that you don't have a seizing/dragging caliper. Next would be to pop the shoes off out back and look at the backing plates, inspecting at the points the shoe contacts. Grooves or ruts are bad here. Wheel-bearing grease on the backing plates if no grooves and move onward. These are cheap (Free) easy fixes that will cross some unknowns off your list of possible problems. Good luck!
-M!ke-

[dchan51360]

That sounds like a bad speed sensor for the abs.

https://www.astrosafari.com/viewtopic.p ... 64#p110170

[dchan51360]

Oops. Didn’t check the year. Is your van a 94? The TSB does not cover pre 95 vehicles but the symptom fits.

[Mmusicman]

Probably an issue with the rear brake shoes/drums.

Front rotors should typically be turned or replaced when new pads are installed... but if your issue is "intermittent"... then that pretty much rules out rotors. My guess is rear brake shoes/drums. Try at least re-adjusting them... certainly give them a good inspection. Drum brakes can be troublesome.

[icebrrg3rd]

I'd go with an ABS issue. Every now and then mine would shudder and shake while braking, altho usually when it was slippery out (wet pavement). Usually would increase stopping distance. Hasn't done it since I removed the ABS...

-Andrew

[MechBob]

possible rear axle seals leaking,oil on rear shoes.

[TurnNburn]

my vote is for wheel speed sensor as well. pull your ABS fuse and then drive it to see if it still does it

[chevymaher]

Change the brake shoes back to wagner thermo quiets. For whatever reason gen 1 vans only like those pads. Everyplace has them. You just got to order them and wait for them.

[xit]

I know, I cannot locate the ABS fuse on my 1994, all I find is a fuse labled Brakes.

[sixsix]

I know, I cannot locate the ABS fuse on my 1994, all I find is a fuse labled Brakes.

You may be onto something...

Just looked at the Manual for the 94 here on the site - pg 6-72 shows that dn in the bot rt cor.
Page 6-73 says: BRAKES, Anti-Lock Brake System and Speedometer - 15 amp.

I would ask at the LPS to look it up as it seems to be a different style than the others in the diagram.
Any progress yet?



Mike

[xit]

It finally warmed up enough, so I took a shot at the rear brakes ( as some of you mentioned) & sure enough the passenger rear
wheel cylinder was leaking just enough to shine the brake shoes up and created the problem. New shoes and new wheel cylinder & the problem went away.

I want to thank all of you who were kind enough to help me out with this problem.

[Mmusicman]

.. I took a shot at the rear brakes ( as some of you mentioned) & sure enough the passenger rear wheel cylinder was leaking just enough to shine the brake shoes up and created the problem. New shoes and new wheel cylinder & the problem went away..

Good guesses:

* ABS Circuitry
* Flaky Fuse
* Caliper Slides
* Backing Plates
* Speed Sensor (twice)
* ABS Issue
* Wrong brake shoes

Closest good guesses:

* Leaking gear oil on rear shoes
* Issue with rear brake shoes/drums

While all the "guesses" may be good answers and are probably something each poster may have experiences with... nothing beats just getting in there and getting a good visual look at the problem first.

Congrats on solving the problem and posting the resolve.