| Author |
Message |
daffycanuck (66.82.9.18)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 01, 2003 - 10:59 pm: | |
I have a large problem...Upon application, I have light to severe chatter in front right brake. The chatter started when new shoes and drums were installed.....4 years ago. The drums were turned on a lathe.
Since then I have replaced tires, Air Pods, slack adjusters, S cam shaft bushings. I swapped rims from side to side....and most recently replaced linings again.
Problem seems to be worse when the brakes are hot and the higher the application, the worse the chatter.
Any ideas???? I'm at a loss.
Jim |
jim mci-9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 02, 2003 - 6:54 am: | |
sounds like the shoes dont fit the drums.... in the old days, shoes were "radias-ed" to fit the drums.. after drums were turned...nobody does this anymore... for example"" the shoes are for a 16" radius... after he drum was turned to clean it up, its radius is 16 1/2"... i'm exagurating for effect, but you get the idea... maybe your shoes are only coming into contact in only a small portion of their lining surface....instead of the whole shoe....if you can see the thickness of the lining as it wears, maybe one area is thinner than the other.... also "premium" linings are "harder" than "standard" linings... this caan cause chatter too....e.... |
John Rigby (24.174.239.244)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 02, 2003 - 7:27 am: | |
Get the exact diameter of the drum,call Luke 1 888-coach-34 and he will tell you the correct pads you need and ship them to bolt on to your shoes. Or if the drum has been cut to deep to match shoes ( and be out of limits ) in this case he will have a new drum.
John |
don (Bottomacher) (216.130.152.51)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 02, 2003 - 7:28 am: | |
Did you replace the brake can or check the diaphragm? |
RayC (142.165.222.233)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 02, 2003 - 3:54 pm: | |
If the drums were turned on a lathe the cutter may have left thread marks. Application of the brakes makes the shoe follow the threads and then it jumps back hence the chatter. Drums should be ground for a non directional finish. Some older brake lathes use a cutter but the feed mechanism jumped and these also did not thread the drum. |
Tim Jones (Torquester) (12.86.9.214)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 02, 2003 - 9:38 pm: | |
Jim,
you could chase a problem like this until it drives you nuts. In my opinion, you should have nipped 'er in the bud 4 years ago when the shoes were replaced....but...since that is too long ago...I would opt for a front brake overhaul. New shoes (yea Jim, they still grind the shoes to fit the radius of the drum) new drums, if the old ones won't turn within specs. and a hardware kit, (includes anchor pins and bushings, s-cam rollers and springs). Check the s-cam shaft and bushings for wear and wheel bearings for adjustment (might want new wheel bearing seals depending upon in/outboard drums. If all of this is done correctly, the problem WILL go away and your peace of mind, and your safety, will be worth the price that you pay.
HTH, Torquester |
Sam Sperbeck (206.230.105.248)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 03, 2003 - 4:20 pm: | |
Hi Daffycanuck,
Have you checked your wheelbearing adjustment? I think too loose wheelbearings can cause this problem, but if they have been loose for 4 years I would expect that you would also have leaking wheel seals by now too, depending on miles driven. Some problems are hard to diagnose so good luck with yours.
Thanks, Sam Sperbeck
La Crescent, MN |
daffycanuck (66.82.9.33)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 07, 2003 - 5:58 pm: | |
Just a rehash of what I HAVE done to correct my problem....
Problem started when I replaced NEW DRUMS with factory TAPERED LININGS....imported from Belgium at a cost of $4,000.00.
Since then replaced slack adjusters, Air Pots and checked bushings for 'S' cam. (OK).
Bearings and seals OK.
Installed new michelin XZA2's. Swapped wheels side to side.
Replaced linings with softer lining.
Still have chatter!!....yes it's driving me nuts. |
daffycanuck (66.82.9.33)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 07, 2003 - 6:01 pm: | |
Forgot to mention, I have also checked for out of round by mounting a dial guage and spining wheel...it is soooooo close to perfect...
Jim |
Tim Jones (Torquester) (12.86.10.178)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 07, 2003 - 9:41 pm: | |
Jim,
When you installed the new softer linings were they ground to match the radius of the drums? Has the hardware been replaced (anchor pins and bushings, s-cam rollers, springs)? Are we talking about outboard mounted drums here? What make and model is the bus? What is the can size and what is the current stroke measurement? Who has been doing the work for you, and what do they say about this? Please help me help you.
Torquester |
daffycanuck (66.82.9.27)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 08, 2003 - 11:29 am: | |
Tim
The Bus is on a DAF chassis. The front axle is a DAF 100N.
The only thing that hasn't been replaced with new are the S cam, rollers, springs....anchor pins? I'm assuming you are referring to the swivel point of the shoe....no they haven't been replaced either.
Can size is correct and stroke is correct.
I did not grind the new soft shoes to fit (the ones I just installed)....I am allowing them to wear to fit.
The problem did not exist before installing the new drums and tapered shoes from the factory. It only chatters when the brakes warm up and are under extreme use....like going down a hill. And as I said before it is ONLY the right side that chatters.
I am doing my own work!!
Jim |
Tim Jones (Torquester) (12.86.9.63)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 08, 2003 - 9:04 pm: | |
Hi Jim,
Here is how I would proceed:
Remove the shoes and drums from both sides and have the drums checked for axial and radial runnout. Have the shoe linings ground to match the radius of the drums (this is a must when new shoes are installed).
Check the radial play in the s-cam bushing (.020" is normally maximum) if it is more than .020" (or in excess of manufacturers specification), replace the bushings and seals and inspect the shaft for wear. The axial play is usually not a factor unless you are aproaching...say...4mm.
Replace the hardware; springs, s-cam rollers, anchor pins (yes, the swivel point), and anchor pin bushings.
Check the wheel bearings for condition and correct adjustment.
Re-install the parts and adjust.
I'd be willing to bet that your problem will disappear.
HTH, TQ |
Gary McFarland (Gearheadgary) (209.128.99.4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 08, 2003 - 9:25 pm: | |
Jim did say that he checked with a dial-indicator, also he checked for play in the S-Cam.
Jut to be inanely obvious, it only happens under hard, extended braking and then, only on the right side.
Have you checked for any differences between the two sides?
Gary |