Intermittent Brake Wobble

[94L C8E]

Don't get too bummed - stick to your guns -finish the rears- I'm still betting you have sticky or stuck rear calipers.. Just pop the pads out, and try pushing in the rear piston, if u have to use a big C clamp to move the piston in, do that / reinstall the old pads after cleaning things with soapy water and you'll fix it.
Also, try down shifting by using the OD button and then brake - I think doing this saves your brake system a lot of heat and work.

 

[baggar11]

I think you still have caliper issues. Specifically the rears. You've only replaced the fronts at this point, correct? That's why it has gotten a little better after you replaced them.

Well, crap. I even waited a week before I typed the last update and I still jinxed myself. Drove down the hill in 90 degree bumper-to-bumper traffic and my old friend is back. MUCH less than before, but back nonetheless.

Not as much wobble back and forth and not much in the steering wheel like before, so I'm thinking the wheel bearings bent locked down took care of that. This is the pulsing brake wobble. It seems like the left and right are almost taking turns braking. Crap. Back to the drawing board.

 

[C6H12O6]

Yes, just the front calipers were replaced. As much as I hate to just throw parts at this thing, I agree that rear calipers are in order. Seems silly to replace every soft brake line and the front calipers at 250K miles only to leave the rears old and crusty. I'll probably do the master cylinder, too, since I'm losing a bit of pressure in the pedal. If I can get all the hydraulic parts replaced and bleed them well, at least I'll know that stuff should be good for the rest of this truck's life. I'm pretty sure my 5K miles a year pace won't ever put another 250K on.

 

[94L C8E]

If you want new, that's cool; or you could just take the pads out & wash the road grit out: pop the support plates out and wash em one at a time, so the floating pad will slide properly; push the caliper piston in (unsiezing it) and pop you pads back in. I did this and cured my wobble, it was free and my rig has 290k and I think they're original calipers.

You'll fix it either way, cheers.

 

[baggar11]

This won't work in all cases or for the long run. If the piston has pitting, pushing it back in without cleaning the pitting(if you can) or replacing the piston(or whole caliper), then you're just moving the pitting further in. Putting new pads in will buy you some time since their thicker, but the wobbles will return once the pitting starts to move back out as the pad thickness decreases.

A rebuild kit for the rears is like $8. Chump change. Rebuild them properly or replace them.
http://www.amazon.com/Centric-Parts-143-91015-Caliper-Kit/dp/B000C04PAE/?tag=ihco-20

If you want new, that's cool; or you could just take the pads out & wash the road grit out: pop the support plates out and wash em one at a time, so the floating pad will slide properly; push the caliper piston in (unsiezing it) and pop you pads back in. I did this and cured my wobble, it was free and my rig has 290k and I think they're original calipers.

You'll fix it either way, cheers.

 

[dtrain]

Drumming this back up... was hoping find the thread about cracked welds on the front end parts (using a crowbar to pry around was what I remember reading... cannot find it again... looking for which location on the front end).

Does anyone know the thread I am describing?

Also, where are you getting your reman'd Toyota calipers?

FWIW, I rebuilt all 4 calipers in about 2 nights, in the garage, and with decent tools. Not for the faint of heart and if piston is pitted... its done anyhow.

Update: found that thread with the cracked frame and location.

Cracked Frame

I found a crack on the frame rail between the steering box and the drag link mount, about 2.5 inches long. I haven't driven the truck in 3 years and don't know when I did this. Now I'm rebuilding my 80 and found this... I hope my parts truck has a straight frame!

forum.ih8mud.com

 

[Therealtotodile]

Wanted to bump this see if anyone has solved a similar issue.

 

[lelandEOD]

Wanted to bump this see if anyone has solved a similar issue.

I've been fighting a very similar intermittent problem for over a year and a half.

I had the truck on a lift last week for exhaust work and noticed this:

I can't say with certainty whether this is ultimately my culprit but I've changed out every other live component in both braking and suspension systems and still have a little bit of death wobble under deceleration (especially going down hill). I've got the DVS frame reinforcement kit which will be installed as soon as the exhaust is done. Then perhaps I'll know whether I've solve this problem.

 

[Therealtotodile]

@C6H12O6 wanted to ask if you solved this ever, my truck currently doing the same thing. replaced everything on rears, drum and all hardware, and even calipers up front, and rotors pads etc. Even did the knuckles and bearing at the same time as the rest of the front end. Also started going after suspension stuff but everything looks good. Stumped as hell.

 

[C6H12O6]

Replied to your DM, but hadn't read your post here. My response won't be of much help. Long story short for others: I replaced hundreds of dollars worth of stuff with incremental improvements, but the final fix was wheel bearig preload and new rear calipers. New bearings hadn't been re-torqued in a while after replacement and they were just not keeping everything straight and happy and the rear calipers were gross. After lots of front and back end bushings, and new steering parts, new brake parts, etc. (all that probably needed replacement at >250K miles anyway) and a fresh bearing service, all was pretty good. Then I sold the 80 and bought a 100 and a 40. Love them both, but still miss the 80.