Shaking while braking even with new Front Rotors

[Boaring1961]

Took my truck into to have my brakes looked at and ultimately fixed to eliminate the shaking and shuttering during braking. The tech said the front end components were pretty tight, but one of the front rotors was warped so I had them do a full brake job, i. e. rotor replacement and new pads. I wasn't interested in having the rotors turned on such a heavy truck that can carry heavy loads.

Afterwards when I drove it home it still shakes and shutters while braking. How susceptible are rear rotors to warping and are there any other items I should check that could be causing this?

Thanks

 

[Kry226]

I've the same thing happen to me on a 2000 Z71. Did the rears and all was well in the world again.

What's the mileage? I just did my Ram's fronts at 140k with moderate towing and the rears were still in good shape. Actually, I didn't even have to replace or even turn the front rotors. Not a hint of warpage.

Hope you find your answer soon, but I am betting on the rears.

 

[Boaring1961]

Thanks for the info Kry226.

I bought the truck (a 2005) used a few months ago and it has 67,000 miles on it. More then 50% of the front pads were still there and the backs have more than 3/4 of the pads still there.

I don't know how the truck was used before me, but there's no fifth wheel or goose neck hitch, but they could have bumper pulled a lot of weight I guess.

 

[jelag]

Its part of a quality brake job to surface the rotors before they are returned to service... each rotor is marked with a discard dimension so that it can't be returned to service when its too thin... thus making the rotor unsafe. .

It is suggested that new rotors be skim cut before placing them in service. .

It's important to know that any dirt, dings, between the rotor and the hub... just a few thousands of an inch will become 15-20 thousandths where the pad intersects the rotor. . just like a flywheel with a ding on the crankshaft.

In the 20 years that I owned my business I'm guessing that 85% of the rotors brought in to us could be turned and returned to service with the specified limits of the manufacturer...

I can't speak to your issue with a low mileage truck... my current truck an 05 has 140K plus with its factory pads pulling my 15K lb 5er... as well as all the work trailers when the business was in operation. . However excessive use of the brakes going down a hill, which overheats the rotors can and will warp the rotors... again, usually turning them will clean them up...

Hope this helps add some insight...

I just read page 2 of the other post... I guess I need to add some additional information... the testing of rotors is first done on the truck with a dial indicator. . any run out. . over maybe . 001" would send the rotor to a rotor/drum lath before it went back on my truck. . We only turned the rotors if we found run out before we tore them down for repair/replacement of pads... . I can't stress enough the importance of testing the rotors before taking them off the truck and doing the same upon installation. . We always lubed the surfaces that allowed the calipers to float so that they can't hang up while they move on their mounts. .

Hot spots show up as a small dot. . sometimes as small as a BB to as large as a 50 cent piece on some large flywheels... if there is sufficient material they (hot spots) can be removed with a grinder instead of cutting the surface... that's why most flywheels are ground and not turned...

Often on larger trucks, Hino, Freightliner, etc with disc brakes we'd grind them because of the hot spots instead of grinding...

 

[Boaring1961]

Thanks jelag for the info. I'd like to save a few bucks and have the rear rotors turned to see if it helps. If I do this would I need to put new pads on or could the existing used pads be put back on?

 

[Bob4x4]

It is not rare that there is not enough meat on the rear rotors of the HD's whereas the fronts can be turned sometimes twice

 

[Boaring1961]

I always thought the front wore faster than the rears.

 

[jelag]

The fronts are designed to do 65% and the rears doing 35% or so. . each vehicle can be different based on the diameter of the pistons in the master and the calipers. . and the sizing of the pads... (surface area) but during the 20 years I owned my business and all the rotors we turned for customers I don't remember a problem with the rear rotors on either the Fords or the Dodges... We found a lot more warped front rotors because of the heat build up, over the rear..... and I can't remember seeing any of them scrapped unless they were run metal to metal...

I know carry a point and shoot temperature sensor... I often get out of the truck while towing at a rest stop and test the rotors and drums... I'm careful to use the exhaust brake all the time and try not to use the brakes over 40 mph unless I need to... I rarely see front rotor temperature over 200* F. and the rears over 150*F with the brake drums o the trailer at 150-175*F... but in a panic stop its not uncommon to see rotor temperatures above 500* and can turn red in an excessive panic stop from 70-80 mph... there is a huge amount of energy moved to the brakes trying to stop 6500 lbs during that stop...

 

[blacksheepdiesel]

Is the shaking and shuddering during braking transferred to the steering wheel? If yes then the front brakes are the culprit. If no then it could be the front or rear brakes.

Did the shop install a new hardware kit with the front brakes? The rubber bushings that the caliper pins ride in can bind and cause the caliper to not work correctly which could cause shuddering or shaking.

Godspeed,
Trent

 

[Bob4x4]

I don't see that on the 3rd or 4th gens. Even if the calipers did not release it would not create a shimmy

 

[Bob4x4]

The fronts are designed to do 65% and the rears doing 35% or so. . each vehicle can be different based on the diameter of the pistons in the master and the calipers. . and the sizing of the pads... (surface area) but during the 20 years I owned my business and all the rotors we turned for customers I don't remember a problem with the rear rotors on either the Fords or the Dodges... We found a lot more warped front rotors because of the heat build up, over the rear..... and I can't remember seeing any of them scrapped unless they were run metal to metal...


I know carry a point and shoot temperature sensor... I often get out of the truck while towing at a rest stop and test the rotors and drums... I'm careful to use the exhaust brake all the time and try not to use the brakes over 40 mph unless I need to... I rarely see front rotor temperature over 200* F. and the rears over 150*F with the brake drums o the trailer at 150-175*F... but in a panic stop its not uncommon to see rotor temperatures above 500* and can turn red in an excessive panic stop from 70-80 mph... there is a huge amount of energy moved to the brakes trying to stop 6500 lbs during that stop...

Apparently yo retired before Fiat took over... . we now are seeing a lot of rear rotor issues with our cars

 

[Bob4x4]

3rd gen front pads last about twice as long as the rears for most guys.

 

[RMacneil]

Thanks jelag for the info. I'd like to save a few bucks and have the rear rotors turned to see if it helps. If I do this would I need to put new pads on or could the existing used pads be put back on?

Replace 'em. If you do things half-*** you get half-*** results. It should only cost you the price of the pads since everything will be apart already. The peace of mind is worth more than the cost of the pads anyway.

 

[jelag]

BOB4X4

I ran a rebuilding operation that re manufactured clutches, brakes, air compressors, and industrial friction... 95% of our work was 3/4 and larger... with 60% in the class 8 truck range, ag, industrial. . we only sold new clutches for cars and turned those rotors and drums, and ground flywheels that the local guys didn't have the tooling to do or didn't feel comfortable with. . We did no installations except for PacBrake. .

We were never the low price guys in town... but I can't tell you how many automotive problems we diagnosed after the kid running the brake/rotor lathe, or flywheel grinder created a problem... To us, it was always about testing and being sure your product was right and tested before it went out the door...

 

[Prairie Dog]

It is not rare that there is not enough meat on the rear rotors of the HD's whereas the fronts can be turned sometimes twice

Last year my rear calipers started sticking bad and got super hot (probably from towing friends boat and dipping in salt water), I found the same thing. With only 80K on the truck the rotors were within . 002" of wear spec although the baked and cracked pads had tons of meat.

The rotors would have worn out before the pads!

 

[Bob4x4]

BOB4X4

I ran a rebuilding operation that re manufactured clutches, brakes, air compressors, and industrial friction... 95% of our work was 3/4 and larger... with 60% in the class 8 truck range, ag, industrial. . we only sold new clutches for cars and turned those rotors and drums, and ground flywheels that the local guys didn't have the tooling to do or didn't feel comfortable with. . We did no installations except for PacBrake. .

We were never the low price guys in town... but I can't tell you how many automotive problems we diagnosed after the kid running the brake/rotor lathe, or flywheel grinder created a problem... To us, it was always about testing and being sure your product was right and tested before it went out the door...

I remember reading many of your post,and Yes I see some pretty sad work come into our shop too. Like why would the op's truck be given back to him with the same problem he brought it in and paid for.....

 

[Boaring1961]

Is the shaking and shuddering during braking transferred to the steering wheel? If yes then the front brakes are the culprit. If no then it could be the front or rear brakes.



Did the shop install a new hardware kit with the front brakes? The rubber bushings that the caliper pins ride in can bind and cause the caliper to not work correctly which could cause shuddering or shaking.



Godspeed,

Trent

The shaking and shuddering is felt in the entire truck and I can't really say it's any worse in the steering wheel. I can't comment on the new hardware kit being installed. I'm not even sure what that would be.



My big conundrum is what to do next. I'd hate to do a rear brake job if it has something to do with the front end. The truck drives super smooth while driving (not braking) and the shaking and shuddering is only while braking, which tells me it has to be in the braking system. If someone thinks there's another potential issue I should check out that's what I'd want to know.



If it is the rear brakes I may want to do the brake job myself and replace the rotors and pads, but I'm a little scared of trying to get the old rotors off, which is why I might opt to have them turned instead. Can someone comment on how to and how bad it is to remove the rear rotors?

 

[Bob4x4]

minus any rust issues the rear rotors are very easy to remove. Remove the caliper and caliper bracket and only the rust/corrosion will be holding them on

 

[Boaring1961]

Will it take a sledge hammer and a lot of beating to get the rusty ones off? Some of the stories I've read sound brutal.

Thanks too Bob4x4 for your help with this.

 

[blacksheepdiesel]

If the rotors don't want to come off easily spray some PB Fabulous Blaster on them and let it soak for a while.

Since the shuddering doesn't affect the steering I would be looking at the rear brakes if it were me.

The hardware kit is simply the rubber bushings and the slide clips for the pads. After taking the calipers off you can slide the pins back and forth in the rubber bushing to see if it slides easily. If not, install new bushings and see what happens.

When the rubber bushings get tight and do not let the pins slide freely what typically happens is the caliper is stuck "away" from the rotor. When the brakes are applied the rubber bushing will "give" enough that the pads can make some contact with the rotor but it will not be the full normal pressure. It is the two forces working against each other that create the shudder. When the brakes are released the rubber bushing will pull the caliper and pads back away from the rotor, thus they will not show abnormally high wear rates. Have seen this on more than one of my 3rd Gen trucks.

Godspeed,
Trent