2nd Gen Non-Engine/Transmission Rear end bounce while braking

[td96ram]

I have done searchs on this and tried some things but it still exists,here is what i have replaced so far.

replaced rear brake shoes,springs,hardware

rear drums resurfaced

new shocks

replaced rear hub seals they were leaking

now i replaced the drums

rotated tires

What am i missing here,this drives me nuts,i know my front rotors have to be replaced but i wouldn't think that would cause the rear end to bounce and i would think if it was u-joint/driveshaft vibration it would be there all the time.

Does anybody have any ideas?The truck now has 120,000 miles on it.

thanks

Tim

 

[td96ram]

Anybody have this problem?

 

[MarkMiller]

What exactly is the problem? Is it a vibration when you apply the pedal or is the back end of the truck hopping when you hit the brakes as in the rear tires are leaving the ground? If it is the first, then the brake drum is warped. If the problem is that the whole azz od the truck hops around when you slam on the brakes that is the springs wrapping up and then the tires breaking traction and sliding and unlaoding the springs then it repeats. Mine does it now that I have removed the rear weight proportioning valve. I have an adjustable proportioning valve that I was thinking of installing to see if it solves the problem. It comes from wilwood.



Or you can solve the spring wrap somehow. Traction links that keep the spring wrap under control would be best. I am going to make some anyway because my springs are too soft. There are a couple of peolpe that offer kits for traction links. Check out Race Care Dynamics, they sell some pimp shiz. Also look at rocky mountain suspension, they sell a few brands. That will solve the wrap but you still may have some shudder out of the back end because the weight bias with these trucks is so towards the front.

 

[THinton]

Hi td96ram, Had the same thing on a 98, hubs was not round. hope this helps

 

[td96ram]

I guess i should have been more specific, but this happens when when coming to a stop, more of a shudder. You really dont feel it if you panic stop more just under normal braking. I just put new drums on,tried unhooking the module for the rear anti-lock,no difference.

Tim

 

[Joe Mc]

td96ram - I had same problem w/my 99. Here's what was suggested by the brake man himself (Sam Peterson), "the shoes need to be 'fitted' to the drums", end quote. Fitting can be accomplished by taking the shoes and drums to a "truck" or "machine" shop, or you can be inventive and figure out how to accomplish this in your own driveway - more on how to do that later. Explained to me what the cause of the "hop" is - when coming to a stop (usually between 35 - 10 mph) the shoes are not making full contact with the drum and are wiggling on the brake plate. Either the shoes are making contact in the mid sections, or only on the top & bottom edges - i. e. they are either a little smaller or a little bigger (around) than the drums and do the wiggle on the brake plate causing a hop in the rear.



Now for the driveway do it yourself method that worked for me: Place drum on work bench, set shoes inside and push them onto the drum surface, observe where the gaps are. I was told you should have . 010" on the heel (top) and toe (bottom) of each shoe. Now to get the shoe frame bent / fitted to the drum. If the space/gap between the shoe and drum is in the mid section of the shoe - place 2 phillips screwdrivers, or round stock if available between the shoe and drum (one on the top/heel and the other on the bottom/toe) while holding the shoe to the drum, and keeping the two screwdrivers from moving place a screw clamp on the center/back of the shoe frame and give it a crank. Be careful not to go too far, then check with feeler gauge for clearance. If the gap is at the heel/toe then place round stock mid shoe/drum and use two screw clamps one heel and the other toe, crank one the other is to hold the shoe in place. Then check gap.



Although this procedure is a real PIA, takes some time and a few choice words, it can be done and once the shoes are fitted the hop is all gone. Oo.



At least it worked for me

 

[td96ram]

I'm willing to try anything,i will give it a shot this weekend and try to get my front brakes changed also ,i will let you know how i works out.

thanks

Tim

 

[Joe Mc]

Tim - It is a bit of a pain like I said. Just have a few cool one's handy and take your time. Joe

 

[td96ram]

Always got some cool ones handy

 

[Joe Mc]

Tim-Forgot to mention while you have all the brake shoes & hardware off the brake plate, clean the brake plate real good and inspect the little humps that the shoes sit on for deep grooves. If there are grooves that are not too deep you can flatten them with a die grinder, smooth them off w/file or fine stone wheel and make sure you put a dab of white lube on them, a little is better than allot. Allows the shoes to return to the non-applied position easier. If you have deep grooves :{ - we used a mig welder to add material and then flatten down. Hope you don't even have to mess with the humps. Also, (man I just keep thinking :-laf sometimes that's dangerous) take the brake self adjuster off, unthread it all the way out and clean the threads real good, then apply some anti-seize to "hopefully" keep the adjuster working. :-laf



Aargh! #@$%! - more thoughts you might want to upgrade to the larger diameter wheel cylinders too . . . you're right there? I got ones for a 97 GMC, 3500, Diesel, 4 X 4, Dually. I know, I know, GM parts on a Dodge?, but the stock brake cylinders on our trucks are like 26mm, the 3500s (Dodge) are like 28mm and the GMC ones are 32mm I think. I got them at Autozone, Brakeware P/N 33708, $14. 99 ea. FYI - says on the bag, "Replaces - Wagner #F79768, Raybestos #WC37337 and Bendix #33708". You should probably get them at NAPA – cheaper and probably Wagners. I don’t deal routinely with the NAPA locally – the counter guys here are like “we know everything because we are big tuff guys (Hanz & Franz types) and you know nothing, you little girly man” :-{} – whatever dork, just get me the part :-laf . . . Have fun Oo.

 

[qkoop]

Can you feel it pulsing in the pedal when you stop. I did my brakes and had that problem. Found out the e-brake was not fully releasing on the passenger side. It would drag and get really hot and would push the brake pedal and feel it pulsing up and down.

 

[LHastings]

I had the same problem with a shutter when normal stopping and thought it was the rear brakes. It turn out it was the front brakes. I replaced the front pads all was okay.

 

[td96ram]

I do feel it in the pedal but i know my rotors are shot maybe its affecting the rear too,i ran out of time this weekend to mess with the brakes i decided to tackle my track bar with a Lindstad kit but ripped the boot but thats another story

Tim

 

[td96ram]

Just a follow up the bounce went away after repalcing my front rotors,calipers,and pads now i have to figure out a slight pull to the right,but i hope new hoses will cure that. Thanks for the input

 

[Jahcad]

Mine does the same thing but only under panic stopping; so does that mean mine is the spring wrapping? Although my front calipers do have 131kmi. on them.

 

[Joe Mc]

Just a follow up the bounce went away after repalcing my front rotors,calipers,and pads now i have to figure out a slight pull to the right,but i hope new hoses will cure that. Thanks for the input

Did you re-install the 3mm spacer on the right side? Make sure air pressure matches left and right sides. And, it could be the r/rear is a bit tight. I'm sure you used some "Sli-glide" (or similar product) on the caliper flats when you reinstalled? SOund like you're there as far as the hop situation. Oo.

 

[Carolina Cummins1]

I know exactly what your talking about!!! I just fixed mine yesterday.



A couple of weeks ago I had new front brakes put on my truck and the rotors turned. The weren't warped, just glazed a little. My brakes has always been very smooth. Until...



Imediately, I felt the brakes pulse and the rear bounce a little. Well, two weeks later it got worst. I remember on my 93 that the brake pads would bind. Sometimes they need a little grease to prevent this. So, I played around and bumped the caliper with a hammer. I hit it at each end a couple of times and test drove it. NO MORE BOUNCE!!!!! The pads were in a bind and not seating on the rotor even.



Try bumping the caliper a few times if front brake work ahs been performed recently. Grease the brake shoe ends were it travels in the caliper.

 

[muchsnow]

Rear brakes, Rear Hopping, brake shudder.

I have done searchs on this and tried some things but it still exists,here is what i have replaced so far.
replaced rear brake shoes,springs,hardware
rear drums resurfaced
new shocks
replaced rear hub seals they were leaking
now i replaced the drums
rotated tires
What am i missing here,this drives me nuts,i know my front rotors have to be replaced but i wouldn't think that would cause the rear end to bounce and i would think if it was u-joint/driveshaft vibration it would be there all the time.
Does anybody have any ideas?The truck now has 120,000 miles on it.
thanks
Tim

(99 2500 2wd) Rear brakes, Rear Hopping, brake shudder, whatever you call it, I had it after replacing drums(new mind you) and shoes on the rear (EGR stuff). You'd practically have to put the fillings back into your teeth after a firm stop. I re-checked assembly (anybody can mix up primary and secondary shoes) a couple of times and convinced myself it was better than good. I disconnected the ABS (pulled the fuse) still no joy, and verified the source to be the rear by stopping using only the emergency brake. It was coming from the rear...

I eventually got on top of it by making sure the hub shoulder was good and clean (scraped off w/a screwdriver while the vehicle was idling with the drums off. ) and inverted the drums on the hubs and watched them turn. they looked pretty round until I propped a screwdriver on a jackstand and checked the contact inside the drum.
These "new" drums were not straight, imagine that... .

I took the drums back to Checker and had them check them on their lathe, I could hear the results of that from the counter where I was waiting. Sooo after waiting to have both drums "trued" Now I've got it all back together good as new (they also didn't charge me for turning the "new" drums).

What a pain though, these drums were not very out of round, but it sure made an extreemly big difference on finally getting through the problem. I guess the chassis is just very sensitive to things of this sort... ... . helps to be very precise on the adjustment between both sides too... ... . not to tight but they should be as close to the same as possible... also a pain w/limited slip diff... .

I also installed the oversized GM wheel cylinders from EGR (oem pass side was leaking), and since it's now working smoothly I really like the feel of the additional assist provided.

I hope this assists someone so's they don't have to spend four days on an afternoons worth of brake work.


Have a good one,