brake problem

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My wife's 98. 0 truck has a new problem. Braking lightly at 25 to 35 mph causes a rapid pulsing of the brakes, apparently from the rear. Lower speeds do not have this effect. Heavy braking does not have this problem either.
I am thinking the RWAL system is flaky. It's still on warranty but I am curious if anyone has seen this.

 

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adiabatic,
It is easy to isolate your problem. Fist make sure you can reproduce the problem. Then try a second time only this time, with your left hand on the emergency brake release, apply only the emergency brake ( not the service brake ). If you still have the pulsation, you know it is in the rear wheels. If there is no pulsation then the problem is in the front. Sounds to me like you have a brake pulsation. Your RWAL system is doing absolutly nothing until you are in a brake lock-up condition. Until then RWAL is just along for the ride!
Good Luck
RK

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98 Properly Valved 4x4 SWB QC ISB A/T Metallic Red w/ tan cloth interior, DC nerf bars, DC two piece mud-flaps, 275 h. p. injectors, Monroe Gas Magnums, Armor Tuff spray in bed liner, Goodyear Wrangler ATS 285/75r/16, BD Heavy Duty Valve body. Walker 21468 thru flow muffler.

 

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I don't know if this applies, but in my 95 model the rear drums were out of round which caused a pulsing/shudder in the rear when braking. The Emergency Brake trick mentioned above should expose this too. The out-of-round was caused by one supplier of the drums to DC. They'd machine the drums and then stand them on their edge before they were completely cool so they'd have more space on their carts and not have to make so many trips across the shop floor. This caused them to sag a little and/or not temper the same around the circumferance. Sometimes the problem showed up right off the dealer's lot and other times it only showed up after several thousand miles. I don't know if they corrected the supplier's procedure or not but the fix was easy (just had them turned once and the problem went away for good) and it was covered by warranty.

Like I said, I don't know if this applies to your 98, just wanted to chime in...



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1999 24V, NV4500HD, QC, 4x4, 3. 54, 8' Bed w/ Rhino Lining, 285/75R16s on 16x8 Eagles, Glasstite high topper

 

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Try jacking each wheel and spinning the whole tire/wheel assembly. Listen close - if you hear a constant dragging sound from the shoes and pads thats good. If you can hear the drum or rotor drag and then release (Pitch of the sound changes) you probably have a warped drum or rotor. Sometimes they only go out of round while hot which makes diagnoses tough. If the problem only shows up after driving a while the temp of the drums/rotors may be an issue. Also check to make sure some gorilla has not over torked your lug nuts and caused problems. Tough to do on a 120-150 ft/lb spec but possible.

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2001 HO 6 speed Regular Cab SLT 4x4 3. 54 anti spin 2500. Used for the daily grind and sneaking away to some secret Baja beaches toting a cabover

 

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I jacked up each rear wheel and found that one has a tight spot when turned by hand.
Took it to the dealer, who predictably found no problem. I went down and drove with the mechanic, and sure enough the problem appeared. "Oh that?" was the comment. "Not bad enough to fix". (under warranty)
I insisted that it was but no go. I asked them to check for a TSB, no go.
We won't be going back with either truck.
Email me if you want the dealers name. I hope DC is monitoring.
I guess I will pay Les Schwab to fix it.

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1997 4x4 CC 5spd, CPL1553 engine, Horton fan, Sport headlamps, 98 shift levers and console...

 

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adibatic,

Just pull the drums and take them to an automotive machine shop (most of the larger parts houses have brake drum turning machines). When you reinstall them, adjust the brakes and you're done (assuming the shoes are in excellent condition.
I'm not surprised they wouldn't warranty warped drums. They'd probably have to split in two before they qualify for warranty. #ad

Mick2500

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2001 2500 ETH/DEE, QuadCab, 4X4, SB, LSD, 3. 54, SLT+, Sport, Intense Blue PC/Agate, Tow Package, Camper Package, 'DC' Bed Cover, Sliding rear window. Ordered 5/01/00... Cancelled 5/30/00... re-ordered 6/02/00... Cancelled again by DC 6/05/00
Gauges (EGT/Boost) and A-Pillar mount Here, 4" Exhaust, Here.

 

[Archive]

Update on the 98: I had the drums turned, it worked for about a week then shudder returned. After some thought, I rotated the wheels back to the way it was from the factory. So far there is no shudder. (But wait a while... )
Evidently, one of the wheels has some kind of eccentricity, that triggers the shudder. I checked the wheel rims for runout they look pretty good, but I have no dial indicator. The Michelin LTX tires look pretty round except for one that has a very small (0. 030?) dip at one spot on the tread. Could that dip be the problem? Maybe it's just enough to start the axle/spring assembly into bouncing on the road, which then starts the cab shaking.
It maybe time to talk the wife into a set of MT Challenger rims.

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1997 4x4 CC 5spd, CPL1553 engine, Horton fan, Sport headlamps, Optima RedTops, 98 shift levers and console... looking for a NV5600.

 

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I think I read in another brake related thread that on some trucks turning the drums is only a temporary fix and that the drums need to be replaced to fix the shudder problem. Don't know if that applies here.

 

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Had the same problem on my 2001. My dealer said DC does not even recommend turning the drums, just replace them. My 99 had the drums turned and the pulsation returned within a few thousand miles.

 

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46wdx, did the new drums fix your problem? At $85 each, I am hesitant to gamble.
I believe your 2001 has the 12 inch drums, correct?
Ours are 13 inch. Made by Bosch.

 

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Hey guys, My 2000 2500 has problems also. The brake pulse is coming from the front discs. It is going to Dodge theis wednesday. Hopefuuly they fix what has to be fixed. Front discs been giving me trouble since day one. Dodge nows they have problems with them so make sure it not your fronts before you start blamin your rears.

 

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Update (last time I hope) on brake shudder:
I bought new drums and shoes from NAPA at a cost of $200. The 98 truck now brakes smoothly just like new. Let's hope it stays that way.
BTW the new drums were made by United, the factory ones were Bosch.
The new ones weigh 40lbs each, the old ones weigh 39lbs each.
I still wish it had disk brakes.

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1997 4x4 CC 5spd, CPL1553 engine, Horton fan, Sport headlamps, Optima RedTops, 98 shift levers and console... looking for a NV5600.