TSB for brake shudder

[Kodiak]

I know I've read about this here, but I can't find the thread. Does anyone know the TSB that covers a rear brake shudder at low speed, low load? The TSB said something about a radiator shim or something...



Thanks.

 

[adiabatic]

Kodiak, I too would like to hear of such a TSB, but I don't believe DC ever confessed to the problem. Try slackening the brake adjusters, replace the rear shocks, and see what happens.

I have removed the linkage from the proportioning valve on the theory that there is feedback from axle twist causing the most violent incidents of brake shudder. So far so good, but the very slight shudder remains.

How bad is yours?

 

[TowPro]

I got bad news. I have new shocks, don't have a proportioning valve on my 2wd, have tryed both tight and loose adjustments and its still have the vibration.



To make matters worse, this summer I replaced the rear brake shoes and drums. Within a month (in which time I did not to anything to over heat the rear brakes, and did not tow anything) the vibration was back.



These were not cheep parts, they are Raybestos top of the line drums.

Originally posted by adiabatic

Kodiak, I too would like to hear of such a TSB, but I don't believe DC ever confessed to the problem. Try slackening the brake adjusters, replace the rear shocks, and see what happens.

I have removed the linkage from the proportioning valve on the theory that there is feedback from axle twist causing the most violent incidents of brake shudder. So far so good, but the very slight shudder remains.

How bad is yours?

 

[adiabatic]

Towpro, that is bad news indeed. We replaced drums and shoes on our 98 4x4 RC and it came right back. I had theorized it was a 4wd problem because of the huge axle blocks but you have shot that down. Plus you have no proportioning valve. We need a new theory here.

How can brake shudder return a few weeks after replacing the drums and shoes?

Any brake experts care to comment?

 

[Kodiak]

adiabatic,



I, too, have tried everything. My last attempt was new tires. The shudder got worse! The only things I have tried that improve the situation are lowering the air pressure in the rears to 40 lbs. or carrying 300+ pounds of weight--both of which are ridiculous fixes.



BTW, mine's a 2WD--so it's not just 4WDs that do this...

 

[adiabatic]

I stopped at a local shop today that has their own lathe for turning drums. The owner said he always turns brand new drums and offered to do ours for $40/drum. He claims that will fix it permanently, I might try it.

He claims that a new drum seems fine for a while because the new shoes have not "broken in". After a few weeks the shoes match the drums and full brake force is possible. Then the shudder becomes evident, he says.

He has an excellent reputation so maybe he is right. He sees a lot of Dodges... .

 

[BertM]

I have run this route before also. The problem seemed to be a combo between front rotor warp and rear drum out of round. I bought brand new Rabestos drums for my brake job, and just for kicks I decided to check for roundness. Pull the tire and old drum off, mount the new drum on backwards(brake surface facing out) with 2 or 3 lugs. Use a jack stand or some fixed object with height, Clamp a stick on top for extention and spin the wheel while riding a dial indicator or dial caliper on the stick for a fixed position. The new drums were way out. I took them back immediately. My old drums were close to true, and new slotted front rotors solved my problem. 94 2500 4x4, 33x12. 5x16. 5. , 5 spd.

 

[sam peterson]

Bert M---Thats excellent diagnosis. Its is hard to explain how factory new product can be out of round that far but we turn 10 to 12 new pieces a day and runout can be from 1 to 25 thou. It doesn't matter if it is US made or offshore. The same is true of the front rotors. When mounting the new rotors to the old hubs they should be turned as a total unit. Sometimes you get lucky but its a lot of work to pull them back off if they shake. ----Sam

 

[Kodiak]

Here's a thought...



Those of us experiencing the rear wheel brake shudder--what size tires are you running on what size wheel?



I'm 265/75/16 on the stock steel. I noticed the shudder got worse when I put new tires on the truck. These are heavier D rate compared to the C rate that were on there...



Just thinkin' out loud here...

 

[adiabatic]

Our 98 is completely stock, ie 245/75/16E Michelins on stock 6. 5 in steel wheels. I have a suspicion that aluminum wheels might help but have no way to check.

I would guess that tire wall stiffness might affect the problem also, as with tire pressure.

Shocks are original too (22k) and pretty weak.

I guess I will put the brake valve linkage back on and get the drums turned.

 

[Motorhead]

Brake shudder

I too turn new drums or rotors for all of my customers. I don't know why they are out of specs but o-well. Also ... check that the rear hub flange is straight and clean of rust around the drum mating surface. Also always turn your drums or rotors with the hubs torqued to the drums/rotors with the bearing races installed. Use a torque wrench on the wheel lugs... not an impact wrench. Last but not least... . don't jam on the emergency brake hard when the brakes are hot. Chris

 

[adiabatic]

Motorhead, I did not know that drums could be turned while on the truck. I knew that the disk rotors could be done that way, it makes sense.

I must be going to the wrong shops, I may have to drive to civilization (Portland)

Regarding the E-brake, I have a hard time believing that such a heavy iron drum would warp under normal usage while hot, unless it came from a 3rd-world foundry.

 

[Motorhead]

Brake shudder

I should clarify that to turn the rear drums with the hubs installed on the drums, you have to remove the hubs from the rear axel assembly... . a chore! The main thing to do is to go to a reputable brake shop or autoparts shop and make sure that the person doing the turning takes the time to make sure that the drum or rotor is properly chucked up in the brake lathe. Also most parts houses, especially if you deal with them regularly will generally turn the drum or rotor (if bought from them) for free..... generally..... Chris

 

[adiabatic]

Re the 98 with brake shudder:

I had the new NAPA drums turned since everyone said it was a good idea. The brakes did not shudder for about 2 weeks then the shudder returned. Apparently the drums cannot hold a circular shape for very long. The E-brake test confirms they are out of round.

It seems the only solution is to back off the adjusters about 30 turns. I suppose this reduces the rear brake efficiency but maybe it's worth it.

We need a disk conversion kit.....

 

[Motorhead]

Something just not right!

adiabatic, it just doesn't seem that the brake drums should be again out of round in only 2weeks. I would take them back to NAPA and have them check them with a dial indicator... not re-turn them. If they are out of round,I would ask them to replace them. NAPA is generally pretty good about warranty. If they hassle you ,start talking louder about safety issues, how your truck doesn't feel safe now. This works well especially if there is alot of customers in the store. DON'T SETTLE FOR SECOND BEST when you have spent perfectly good money for quality parts! Let us know what you come up with. I have E-mail allert. Good Luck... Chris

 

[HEMI®Dart]

Seems Dodge is aware of the problem, and working to find a fix.



more info: http://www.dodgeram.org/tech/tsb/2000/xx-xx-00.htm

 

[HomerDog]

Just to chime in, I have put new Rancho shocks, Michelin tires, and just did the rear brakes this week (and upper/lower ball joints, and 5 inch tip--The shudder is the same as before all of this. I thought it was the rear brake, and they were bad, but that didn't solve the problem. Soon as I have any load on it they work fine.