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john_lessard Samba Member
Joined: September 12, 2017 Posts: 103 Location: Boston, MA
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Posted: Thu Oct 22, 2020 6:15 pm Post subject: Scraping Sound from the Rear |
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Hello all!
My friend and I recently finished overhauling the suspension on his 1991 Vanagon Tin-Top, 2WD, stock 2.1L, stock 4-speed transaxle. The overhaul consisted of Schwenk Springs, Bilstein Shocks, Powerflex bushings, rear brake shoes and backing plates, rear bearings, and some other odds and ends. The van has been driving great since we finished (and after a professional alignment) minus this one concerning noise..
When the van turns hard, a scraping sound can be heard from behind the firewall under the rear bench. It is hard to pin down exactly where its coming from behind that wall. During a test drive where my friend drove around in a circle, we could consistently replicate the noise. I was able to capture it by lying under the rear seat and recording it. The video of the noise is linked here:
https://youtu.be/Z5PG1Uo7wqI
We have loosely ruled out the new aftermarket backing plates rubbing on the drums because this was happening at first and made a different scraping noise. Our solution to that was to shim the drum off the backing plate. I am suspecting the the old CV axles are unhappy with new height but the sound doesn't seem consistent with CV joint failure. I also remember pressing in the inner rear bearing past the flush point. I can't imagine that is causing this issue, but I wanted to throw that out there.
Thank you all for the help in advance! Here's a pic of the work for fun:
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17112 Location: Retired South Florida
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Posted: Thu Oct 22, 2020 8:07 pm Post subject: Re: Scraping Sound from the Rear |
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How did you shim the drum off the backing plate? _________________ ☮️ |
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john_lessard Samba Member
Joined: September 12, 2017 Posts: 103 Location: Boston, MA
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Posted: Fri Oct 23, 2020 11:12 am Post subject: Re: Scraping Sound from the Rear |
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I used 0.5mm spacers sourced from McMaster-Carr. Drum rubbing on aftermarket backing plates seems to be a common problem on Split-Window buses. The rear drum assemblies on Vanagons are very similar, so I followed their suggestion and shimmed the drum. Not a forever fix I know, but it worked great in a pinch and the backing plate scraping was solved.
To be clear, the scraping I am describing now existed before we shimmed the drums to fix the backing plate issue. I do not think these noises were related. |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17112 Location: Retired South Florida
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Posted: Fri Oct 23, 2020 11:44 am Post subject: Re: Scraping Sound from the Rear |
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5 around the studs? The vanagon brake shell has no strength in the face. It depends on being sandwiched between the rim and the drive flange hub. Lug torque is 115 or so foot pounds. I would not assume the shimming is not the cause.
Take some spray paint and paint the outer lip of the drum and the backing plate. Determine where it rubs. It’s probably easier to have the drum machined for clearance if it’s rubbing vs the installed backing plate. _________________ ☮️ |
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john_lessard Samba Member
Joined: September 12, 2017 Posts: 103 Location: Boston, MA
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Posted: Tue Apr 20, 2021 9:23 am Post subject: Re: Scraping Sound from the Rear |
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When we revisited this problem recently, we looked more closely at the new JP backing plates. After some slight bending of this plate, we were able to eliminate the scraping sound due to some component rubbing against the drum. We also removed the drum shims.
We rebuilt the CV axles with Lobro joints. This solved any grinding sound we herd from hard cornering. _________________ 1986 Tin-Top Vanagon, 2.0L Zetec, Peloquins TBD 2WD |
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whafalia Samba Member
Joined: January 28, 2009 Posts: 685 Location: San Francisco
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Posted: Tue Apr 20, 2021 8:01 pm Post subject: Re: Scraping Sound from the Rear |
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Happy ending! Good work!! _________________ 84 westie 2.2 w/ digijet, AT |
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