Rear Brake Vibration When Braking

I have a 2000 SR5 4x4 with the 4.7.

The problem I’ve been having is a really bad vibration coming from the rear along with the brake pedal pulsing when I apply the brakes. I know it’s the rear because when I’m going down a stretch of road and I lightly apply the parking brake the truck begins to shake.
I never had this problem until I got my parking brake working and properly adjusted.

Things I’ve done to attempt to fix the problem and their results:

I assumed it was a problem with the drums being out of round so I bought and installed brand new power stop brake shoes and Rabestos drums. I reused the hardware as it was in good shape.
This unfortunately did not solve the issue In fact it made it worse.

In response to this I took off the drum flipped it around on the hub and used spare lug nuts to secure it. I then used a magnetic base dial indicator to measure the runout of each drum. The passenger side had 0.005” and the driver side had 0.025”. I also preformed this test on the old drums and they had 0.020” and 0.025”.

After discovering my brand new drums were worthless I packed them up and returned them and had the old drums turned on a brake lathe.

I reinstalled the old but freshly turned drums the problem seemed to go away during the test drive and the drive to work the next morning.

However, on my way home from work the vibration and pulsing of the pedal started to come back. At first it was mostly in the pedal and now it still shakes the truck but not nearly as bad.

I am completely stumped on what else could cause this problem and was hoping someone more knowledgeable than me could maybe point me in the right direction.

 

Any sound associated?

When was the last time you bled the brakes?

When you bled the brakes, did you also bleed the Load Sensing Prop Valve ("LSPV"), mounted on the framerail, above the axle?

Not that I think air would be the issue, but asking. My first suspect was out of round drums, but you had the old drums turned. My next suspect would be either the spring kit used or wheel cylinders, Aisin makes OEM replacements.

 

I had the exact problem on a First Gen Tacoma after I changed out rear brake shoes and drums. Truck vibrated badly on braking and isolated to rear by applying parking brake. I didn’t do a run out check on drums as they were brand new (Rock Auto) but I did put a dial indicator on axle hubs and found the left was way out, same wheel someone crashed into wife long ago. I took it to Meineke and told them about the brake problem and what I found and to change out the axle.

They called a few hours later and asked where I got the drums from and that they were trash and the truck was fixed. When I picked up the truck the vibration was still there but not nearly as bad, and after a couple of weeks it was completely gone. Like the rear shoes bedded into a sweet spot or something?

 

I recently had the same vibrations from my rear brakes even with new drums, shoes, and wheel cylinders. My problem was rear drums weren't OEM and were out of round probably out of the box or soon after. I know you got your old ones turned, but I'd recommended throwing OEM on there (maybe wait for the next sale on online Toyota parts from a dealer with free shipping, I used Serra Toyota was about 100 or so per drum shipped). This is what solved my issues with the whole truck vibrating and pedal pulsing when coming to a stop.

 

No sound that I can hear.

I bled the brakes right before I put on the first set of drums I got.

I don’t know if this is relevant but the reason I bled them was I had a axle seal and wheel bearing go bad on the passenger side, so I had the axle shaft out for a week because I had to weld up the special bearing puller.

I did bleed the LSPV and both rear drums but not the front calipers, I don’t remember what order but it was according to whatever your post about brake bleeding said.

I haven’t changed the wheel cylinders but I can’t believe they’d cause a vibration like this.

 

I am dreading this is the solution.

I just spent $50 on getting these drums cut. And I know I’m being cheap but I find it hard to spend $100 per drum.
To me that’s just ridiculous.

 

That’s one thing I forgot to check while I had the wheels off the other day, whenever it stops raining here I’ll check and see if my axles shafts are bent.

 

I'd give it a week or two and see it it goes away ... the only reason I took it to a shop was because at the time I didn't have the equipment to change out the axle and I thought that was the problem. OEM parts may have prevented the entire situation, but ya, OEM pricing on common maintenance items is ridiculous. Lessons learned.

 

Yeah, the old ones lasted 25 years. $200 to get another 25 years out of them does seem absurd

 

Try backing down your star wheel a turn or two. These FGT's do not like rear drum brake shoes adjusted up tight. Back them off a few teeth and see if it gets better.

 

Most auto shops will machine a drum or rotor for you, costs about $25

 

The rear drums are automatically adjusting. You can back them off, but that A, will effect your entire braking system negatively, and B, if you adjusters are working properly, will just get reset back to where it belongs the first time you use your parking brake again.

Now, if you didn't use the auto adjuster to set them in the first place, its not a bad idea to back them off and then let the adjuster do its job properly, as if you tried to do it yourself it likely was done wrong.

 

Not entirely correct. There is a TSB about the problem and Toyota's fix was to replace the adjusters with an adjuster having fewer teeth so they would not self adjust too tight. When installing new shoes people have a tendency to manually adjust then too tight in which case the fix is to back off the star wheel a turn or two, and it will not negatively impact the braking system.

 

Where can I find this TSB?

 

I backed both adjusters off so there was no drag on the brake shoes. I cycled my parking brake about 5 times to set the adjustment.

After doing this it seemed to fix the problem. But now my passenger drum is dragging and getting a lot hotter than the driver side. It’s so much to the point where I could smell it while sitting at a light.
Both rotors: 220°
Driver Drum: 140°
Passenger Drum: 250°

 

Did you recheck your e-brake cable adjustments? Are you sure you backed the adjusters in the right direction? (see diagram)

 

Here you go. There is also a later TSB that offers a heavier brake drum in addition to the star wheel adjusters.

 

I wonder, if both adjusters are the same or one was replaced, by the proper tooth count one, and one was not?

 

I’m fairly certain my cable is adjusted correctly. And I’m 100% certain that I backed them off correctly

 

Yea I was wondering that as well, I’ll have to pull the drums off again and check.

 

When you do make sure the interior e-brake cable has the correct amount of slack and make sure that cable is routed correctly down under the guide.