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sporatic clunk from front end drove me nutz
https://slantsix.org/forum/viewtopic.php?f=13&t=65327
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Author:  wjajr [ Mon Sep 14, 2020 10:05 am ]
Post subject:  sporatic clunk from front end drove me nutz

Last year I disemboweled the running gear on the 67 Dart. It involved every change needed to go from small bolt pattern to four wheel disk brakes. I got most of the new parts from Doctor Diff including the B body slider front disks which most likely were on our showroom fresh 1976 Cordoba which we drove for 80K miles over six years, with no clunking from pot hole & frost heave ridden New England.

Fast forward to this summer driving the Dart. I replaced the crappy Addco front sway bar that had poor attachment geometry and lots of squeaking from day one in 2008 with a Hotchkis 1 1/2 inch bar that has correct geometry attachment similar to what the factory used. A lot of the racket from moaning groaning and squeaking is no more. Happy Happy Happy. But there is an occasional hard sounding clunk when rolling over cretin pavement irregularities that is now driving me nuts.

This weekend I rotated the two front tires side to side, and tried to figure out where the heavy clunk sound was coming from. Everything on the front was still torqued to spec, shock bottom bolts were tight, brake pads were fitting tight with their field bent tab. What I did discover was the calipers were able to be pried up of their slider perch with a large screwdriver that when driver was removed the clunk reviled it self.

Those tinny SS steal attachment clips were still torqued down correctly, but they had deformed slightly allowing some vertical movement when driving over rough pavement, rail road tracks etc. I removed and re bent the clips on one side so it has more holding force applied to caliper, and a lot of the clunking went away. So I have ordered a new set of retainers, and will replace those now on the car.

This clip retainer method of securing the calipers to the slider rails seems to be real flimsy. I understand this stile of brake was in use for a number of years (73-89) by Chrysler; I assume without any real problems.

Has anyone out there in slant land had this problem?

Author:  Greg Ondayko [ Mon Sep 14, 2020 1:02 pm ]
Post subject:  Re: sporatic clunk from front end drove me nutz

This can be a problem on the oe chryco sliders.

I don't know what the proper spec is between the sliding caliper and the ways that they slide on.

I ruined a set of ways by filing them adding too much clearance in the process. That was on my 77 3/4 ton truck.

I swapped the ways or sliders out for "new" ones from a 1975 3/4 ton parts truck. Solved the noisy brake caliper problem.

I would say the clearance is small like 0.020"-0.025" or something.

I don't think this is a problem that can repaired.. as a baind aid I remember dealers and parts stores offering giant rubber bands to hold the calipers into the ways on fleet police and Taxi FJM bodied cars.

If your clunking is what I think it is you need to replace the sliders.


I wonder if any of the aspen/ volare forms or dippy.org would be of help?


Cheers!

Greg

Author:  matv91 [ Mon Sep 14, 2020 1:05 pm ]
Post subject:  Re: sporatic clunk from front end drove me nutz

viewtopic.php?f=13&t=58938

Author:  wjajr [ Tue Sep 15, 2020 7:54 am ]
Post subject:  Re: sporatic clunk from front end drove me nutz

All new brake parts less than 800 miles on installation.

I don't recall any rubber "O" rings in the kit when I installed the front disk brakes. I did lube the slides with a light coating of silicone grease per instructions, and a test slide before installing pads produced smooth movement.

Checking my recent order of disk brake hardware kit; Raybestos part number H5516A shows it includes the "O" rings. In a few days I'll have that item in my mailbox, and then installed on the car.

We'll see if that fixes the problem. If not, I'll call the state, and local towns requesting they repave all of the crappy roads around central Maine...

Author:  Greg Ondayko [ Tue Sep 15, 2020 8:19 am ]
Post subject:  Re: sporatic clunk from front end drove me nutz

wjajr wrote:
If not, I'll call the state, and local towns requesting they repave all of the crappy roads around central Maine...



While you are at it and on the horn anyway can you do the same for Wesmoreland County in PA?


Greg

Author:  wjajr [ Fri Sep 18, 2020 6:57 am ]
Post subject:  Re: sporatic clunk from front end drove me nutz

Greg:
Quote:
While you are at it and on the horn anyway can you do the same for Wesmoreland County in PA?

Consider it a done deal. Emails going out now, expert to see smooth roads by November.

Power of the pen baby!

Or, just another shovel load...

Author:  wjajr [ Mon Oct 05, 2020 11:16 am ]
Post subject:  Re: sporatic clunk from front end drove me nutz

So back on Sep 15 I was awaiting new brake hardware that attaches caliper to sliders. It arrived a few days later than anticipated, and by then the project got shoved over to the back burner while work on the 67 International pickup truck got hot and heavy, and work on res-erecting a 1950 Mark VI Bentley occupied the time... My friends car is silver, with black wings and boot.

So it's now Oct 5, and I just changed out the brake hardware on the Dart and also installed those silly rubber bands. Brake clunking is now gone. There were two clunks, one when applying brakes backing up, and occasionally driving through a field of pot holes or very irregular pavement.

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