Vibrations while braking

Hello everyone, I have a 99 Tacoma 4x4 with the 3.4L that I am having trouble with. I can't seem to get rid of my rear end vibrations, it's most prominent while braking, but I do still occasionally have it cruising on the highway, but the highway vibrations are not as common and not predictable. It seems to be only when the braking vibrations are extra bad. It does seem to get worse with heat.

I can feel vibrations in the seat and the brake pedal, I have performed the ebrake test to isolate the vibrations are not from the front. So far I have replaced:
Drums x2 sets
Shoes x2 sets
Drum hardware
Wheel bearings
Axle seals
Drive shaft center bearing

I'm really getting to my wits end with this issue. I'm trying to get the brakes sorted so that I can replace my frowny leaf springs and worn shocks. Is there any chance the worn out springs and shocks could be causing this? The vibrations almost feel like the shoes are grabbing and slightly releasing as I hold the pedal constantly. After my first set of replacement drums I thought maybe I just got a bad drum from AutoZone, I replaced them after that and I still have the issue. I guess it's possible I've had 4 bad drums, but not likely.

Any ideas?

 

maybe warped rotors.

Does the steering wheel move back and forth a bit when you are braking and feel the vibes?

 

I'm not sure why warped rotors in the front would not show vibrations from the front and feel though the steering wheel though?

 

Vibes from under the seat and pedal could very well be coming from the front.

Warped rotors will cause vibrations when braking and will be felt through the steering wheel in most cases.

 

I see no mention of tires .

They can cause all manor of vibrations

one lug nut tighter then the others can cause interesting vibrations .

Even the road Surface

 

Tires can for sure cause vibes.

also, check for play in your ball joints.

 

What brand rotors and drums did you get. If you got them from AutoZone there is your problem. Go back and get OEM stuff.

 

PowerStop makes great drilled and slotted rotors. So does EBC.

 

I do not feel vibrations though the steering wheel, the front rotors have good turnout and pads are at maybe 2/3 life. I only did the rear brakes because i popped an axle seal and contaminated the shoes. Before this I didn't have any issues. I did go with AutoZone drums and O'Reilly shoes. Usually on previous vehicles they have been just fine. What makes them inferior to OEM for the Tacoma?

The tires are at about 1/3 life left, and have been balanced recently.

I guess the major giveaway for me is that the vibrations started after I did the axle seals and bearings.

I do notice if I set the shoe clearance looser I notice less vibrations, which also leads me to believe it's a shoe or drum issue. Does Toyota have any kind of warranty on parts? I do like that these drums and shoes have a 2 or 3yr warranty

Thanks for the help so far!

 

Not knowing you experience level on repairs... when you removed the drums, did they pull off easy or did you have to thread a bolt in the drum to seperate the drum from the axle flange? Slight posibility that the drum(s) are not sitting flush on the end of the axle flange, the holes where the studs go through might not be radiused on the inside... anything that will not allow the drum to sit flush. If the shoes are not adjusted properly, too tight, and they contact the drum all of the time, the drum will warp and cause a vibration. When you put the shoes back on did you put the "big shoe" in the back? Did you "white grease" the contact points of the shoes to backing plate? Are there grooves worn in the backing plate that might hang the shoe and not allow it to retract? Is your e brake the twist and pull type and if so, how many clicks before it gets hard to pull? Very tought to figure out not being there.
Just thought of one more thing... have you greased the driveshaft... when you brake the rear axle rotates counter-clockwise when viewed from the D/S of the vehicle and maybe you are feeling the U-joints... long, long, LONG shot on this.

 

Removal of the old drums was easy, they slid off without using the thread bolt holes.
The shoes I have only allow fitment one way. The ratcheting assembly must mount to one shoe, so I had to install as they decided from their factory. I set clearances loose enough that the shoes just barely graze the surface of the drum when installed and rotating. I did not count the number of clicks/pulls on the ebrake/adjustment lever. I did lightly sand/lube the shoe contact points. As for the ebrake I can't recall off hand how many clicks either, maybe half the throw available?

 

I also suspected I might have bent axles, so I lifted the rear and had my lady start/drive the truck while I watched the wheels for oscillations, I did not see any so I kind of ruled that out as well.

 

damn... you covered all of the easy points.

 

Yeah, that's why I don't understand why it's still happening

I just got dealer prices on drums and shoes, it's 150/drum and 85 for the set of shoes. I only paid 50/drum and 20 for the set of shoes at autozone. What peeves me is that if I spend this $400 on brake parts at the dealer, its not a guaranteed that my problems will go away either.

The only parts I haven't replaced are axles, wheel cylinders and hubs. The leaf springs are on their last leg, so I'm thinking MAYBE there is enough play in the springs that the whole axle is experiencing a precession of some sort while braking. It might be winding up like a clock and then releasing which may give me the brake/release symptoms I mentioned. I might throw a GoPro under the truck tonight and see if I can get anything on video.

 

What was the cause of the seal failure ??

Unless it was a clogged vent

This might lead to your problem.

 

I believe either clogged vent or wheel bearing, I replaced both bearings and the vent was not clogged unless debris fell out during removal.

 

Turn the drums,just went through this myself.the drums I got from Napa were out out round.turn the drums...I bet you will see a difference.

 

Was this resolved? Having similar problem replaced rear drums 2x from Autozone.

 

I have an update to the braking vibration. A new set of warranty rotors and rear drums and pads reduced but didn't fix the problem. We dealt with it for about a year. This weekend while offroading my sway bar came off on the drivers' side. The bushing was torn and I replaced and tightened everything up. I must have had some play in the sway bar that was allowing the vibration. It drives and stops very tight now.

 

Make sure that all of your wheels are balanced and tire treads are even not scalloped.