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Tcash
Samba Member
Joined: July 20, 2011
Posts: 12843
Location: San Jose, California, USA
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 Posted: Wed Nov 25, 2015 3:12 pm Post subject: Brake drum rubbing (Grinding) on backing plate |
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| [url=http://www.thesamba.com/vw/forum/viewtopic.php?t=643031&start=0&postdays=0&postorder=asc&highlight=]Brake drum rubbing (Grinding) on backing plate[/url] |
First off I would like to thank everyone that contributed to this subject!
Brake drum rubbing (Grinding) on backing plate.
Causes of this is include:
New Backing Plates installed.
Hub, Drum or Wheel bearing Spacers are worn.
Vanagon Brake Drum.
Let's start with the most common problem.
New Backing Plates 211 609 425 L/R installed.
Note how the drum is just kissing the raised portion of the backing plate.
Please do not bend the backing plate. The brake shoes are attached to it and this will cause uneven wear of the shoes and the drum.
There are three fixes for this.
1. Install new updated rear wheel bearing spacers 211 501 281 E. Oddly when this part was updated the part number did not change? This will require removing the outer wheel bearing race or machining the new wheel bearing spacer down so it will fit through the outer wheel bearing race.
Page 62 in the Bentley notes:
"Spacer sleeves with an outside diameter of 42 mm (1.654") and 46 mm (1.811") have both been installed during manufacturing. However, only the 46-mm sleeve is available as a replacement part. If one sleeve must be replaced, also replace the sleeve at the opposite rear wheel."
Thanks to SGKent, he discovered that not only where the new ones larger in diameter. But where also longer in length by .050".
Rear Axle measurements/SGKent
This will space the Hub and the Brake drum .050" out from the Backing plate and not allow it to rub.
2. Shim out Hub/Drum. Install Alternator/Generator pulley shims 111 903 131 A, between the Hub/Drum and the Wheel bearing or Spacer ring. Shims are 0.5mm thick. Adjust accordingly but two or three aside should do it.
3. Take the brake drums to a machine shop and have them cut .050" off the face of the inner lip. The part that rubs against the Backing plate.
Hub, Drum or Wheel bearing Spacer Sleeve is worn, where they meet.
Note that all the areas indicated in Red are sandwiched together by the axle nut #9 and held in the bearing housing by Purple #18 retaining ring. If the nut is not tightened correctly, these areas can wear. Allowing the drum to rub against the Brake backing plate.
71-79
68-70
1. Replace worn parts.
2. Shim out Hub/Drum. Install Alternator/Generator pulley shims 111 903 131 A, between the Hub/Drum and the Wheel bearing or Spacer ring. Shims are 0.5mm thick. Adjust accordingly but two or three aside should do it.
3. Take the brake drums to a machine shop and have them cut the face of the inner lip. The part that rubs against the Backing plate.
Vanagon Brake Drum
Thanks to germansupplyscott
Bus and Vanagon drums compared
Bus drums are 2.53 mm and Vanagon's 2.68 mm at the mounting surface.
Vanagon drums are 0.15mm thicker at the mounting surface and the inner lip is machined differently.
Qoute: germansupplyscott:
"It's easy to get Vanagon & late Bay Bus drums mixed up, even the big companies who distribute parts do it."
"The difference between a Vanagon drum and '71-'79 Bus is the outer edge where the drum notches around the backing plate, the Vanagon drum has a wider groove in this area. you'll only find this out by looking really closely or by installing a drum on the wrong vehicle and it will either rub the backing plate or not fit over it."
1. Return the drums and get the right parts.
2. Install Vanagon self adjusting Backing plates with hardware and shoes.
3. Although the outer lip can be machined off. It is not advised.
Hope it helps
Tcash
Please let me know if any editing is necessary.
Last edited by Tcash on Sun Aug 06, 2017 10:11 pm; edited 2 times in total |
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kreemoweet
Samba Member
Joined: March 13, 2008
Posts: 4145
Location: Seattle, WA
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| Posted: Wed Nov 25, 2015 4:06 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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I just recently overhauled the rear brakes & bearings on my '71 bus. When I got the bus in 1995 it had original backing plates, and the new
46 mm diam. spacers along with the later outer roller bearings with rollers captive to the outer race. This meant that the hub/bearings could not
be easily disassembled for inspection/repack - so I didn't. When I overhauled them a couple of months ago, I replaced the large spacers with the original 42 mm
ones. Both the large and the small spacers (and a spare 42 mm set I have) were all precisely the same length (42.75 mm). I also replaced the
old '71 backing plates with the shoddy new Brazilian VW ones. There was no rubbing between drum and backing plates in either the new or old
setup.
So it does not seem to be the case that the new backing plates will necessarily cause rubbing (even though they have those raised areas, pointed out above,
that the old ones do not). It also seems that current 46 mm spacers are a bit longer than they used to be.
Always my pleasure to muddy the waters a bit.
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Tcash
Samba Member
Joined: July 20, 2011
Posts: 12843
Location: San Jose, California, USA
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| Posted: Wed Nov 25, 2015 4:18 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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Good info.
There has been a number of members that have reported rubbing. I wonder if it is a manufacturing tolerance issue or if the Backing plates where made by different manufacturers?
Thank you
Tcash |
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Cptn. Calzone
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Joined: June 27, 2007
Posts: 1884
Location: S>E>Alabama
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| Posted: Wed Nov 25, 2015 4:21 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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yup you are good at it
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Amskeptic
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Joined: October 18, 2002
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Location: All Across The Country
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| Posted: Wed Nov 25, 2015 9:18 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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I have had hit-and-miss backing plate rubbing issues that are caused by All Of The Above. There is no magic bullet that will guarantee that you do not get hit with this annoying issue. You can, however, improve your chances for a relatively painless installation of new backing plates.
A) If you get rubbing with your original equipment that develops slowly, you have wear going on in the rear wheel bearings that quickly will cause deterioration of the drum thrust surface in the early buses.
See the November 2013 write up with colorized photographs for the places that commonly contribute to rubbing over time:
http://www.itinerant-air-cooled.com/viewtopic.php?f=47&t=11737#p204120
I did add a spacer between the drum (early) or hub flange (late) and outer bearing spacer/race during an itinerary because I still had 6,000 miles to knock out. This horrendously tacky solution worked just fine. The 1600 fan shim gave me an additional 40,000 miles with no appreciable wear and quiet rotation until I replaced the drums this past summer. However, the symptom of rubbing is indicative of the need for further investigation. The culprit may be a wheel bearing housing beginning to wallow out. That is what I have with my 1970 bus, and the only cure is a new fresh wheel bearing housing . . .
Remember that the composite drum buses (flat hubcaps/wheel nuts introduced for the 1971 model year) do not locate the axle shaft/hub/drum with the outer bearing. The outer roller bearing is free to axially float. The inner bearing's shoulders and circlips are the thrust control areas to blame if rubbing is chronic and incureable. The solution is nicely crafted and polished spacers along with your promise to keep the axle nut fully torqued. These axle nuts lose torque not because the nut backs off, duh, see that cotter pin?, but because the clamping force diminishes if movement amongst the stack of inner rotating bearing races/spacers. Keep the nut torqued, no wear, everything's good.
B) If you have installed new (questionable) backing plates that rub, and it is not due to poor dimensions, it could be shipping damage that has ovalized the circle. Hey, have fun making it a perfect circle again, you have a millimeter clearance or so to play with over the full diameter of the backing plate/drum.
C) Where possible, I will attack the new part with a dremel before I touch my good German original parts. Spritz it with high temp black paint when you are done. The new backing plate *must have* the sealing goop suggested in the Bentley between it and the bearing housing. It can contribute to rubbing, by the way if you get carried away, so be sparing. Make very sure that you clean the big dowel and the big dowel hole at the adjuster anchor. You need to have the backing plate fully seated to the wheel bearing housing to optimize the distance between it and the drum.
Colin
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Tcash
Samba Member
Joined: July 20, 2011
Posts: 12843
Location: San Jose, California, USA
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| Posted: Wed Nov 25, 2015 10:46 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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Thank you Colin.
Tcash |
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aeromech
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Joined: January 24, 2006
Posts: 17745
Location: San Diego, California
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| Posted: Wed Nov 25, 2015 11:34 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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Here's how I resolved this a few years ago
http://www.thesamba.com/vw/forum/viewtopic.php?p=5683242#5683242
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Smurf
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Location: Colmar, PA
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| Posted: Thu May 19, 2016 4:02 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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I just took off my backing plates today...oh man they're thin and have rot holes throughout 
Are these http://www.busdepot.com/211609425pr backing plates the only solution?
Are they better than the ones pictured that caused the rubbing?
Has anyone had any issues with the bd ones?
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lolight70
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Joined: August 22, 2013
Posts: 160
Location: West Australia
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| Posted: Thu May 19, 2016 4:40 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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Slightly different issue but related
I am in the process of replacing the rear hub bearings,
I have no drum rubbing but i have a bit of play when i pull on the wheel in and out.
When i spin the rear wheel,it all seems smooth(CV removed)
The hub nut was torqued super tight,bearings look oem
Will new bearings fix the problem ?
Thanx
Chris |
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SGKent 
Samba Member
Joined: October 30, 2007
Posts: 42936
Location: at the beach in Northern Wokistan
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| Posted: Thu May 19, 2016 6:38 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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| Smurf wrote: |
I just took off my backing plates today...oh man they're thin and have rot holes throughout
Are these http://www.busdepot.com/211609425pr backing plates the only solution?
Are they better than the ones pictured that caused the rubbing?
Has anyone had any issues with the bd ones? |
If they are indeed genuine VW they are actually the 251 part sold as 211. As Ron at Bus Depot BusDepot to be sure but I believe that is what is sold today. If you use that part then the spacer inside on 1971 - 1979 has to be the longer one or you will have to mill a little off the brake drums so they don't rub - especially when turning.
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SGKent
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Joined: October 30, 2007
Posts: 42936
Location: at the beach in Northern Wokistan
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| Posted: Thu May 19, 2016 6:44 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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| lolight70 wrote: |
Slightly different issue but related
I am in the process of replacing the rear hub bearings,
I have no drum rubbing but i have a bit of play when i pull on the wheel in and out.
When i spin the rear wheel,it all seems smooth(CV removed)
The hub nut was torqued super tight,bearings look oem
Will new bearings fix the problem ?
Thanx
Chris |
Chris - Knowing if those are too worn is a feel thing for most mechanics. They have to move a tiny bit so grease can move around but it is not very much. See that doesn't help you but I wish it did. How do the two sides compare? How many miles on them?
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).
George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."
Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice" |
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Busdepot
Samba Member
Joined: March 24, 2004
Posts: 1359
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| Posted: Fri May 20, 2016 1:39 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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| SGKent wrote: |
| Smurf wrote: |
I just took off my backing plates today...oh man they're thin and have rot holes throughout
Are these http://www.busdepot.com/211609425pr backing plates the solution?
Are they better than the ones pictured that caused the rubbing?
Has anyone had any issues with the bd ones? |
If they are indeed genuine VW they are actually the 251 part sold as 211. As Ron at Bus Depot BusDepot to be sure but I believe that is what is sold today.. |
The ones we sell come from Volkswagen/Brazil and are Bus ones. They have the 211 part number right on them. We've been selling them for nearly 20 years and I have never had anyone report a fit issue.
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kreemoweet
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Joined: March 13, 2008
Posts: 4145
Location: Seattle, WA
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| Posted: Fri May 20, 2016 4:27 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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For your information: the illustration that BusDepot is using on their website for the bus backing plates is not an accurate representation of
what they are selling. That illustration shows NO extra raised portion (which seems to be the source of most drum interference problems), the
hand brake cable entrance is different, and there are no holes for the hold-down pins. The ones I received from BD differed in all those areas.
Seems to me only a minimal effort is required to put up a photo of the actual part being sold.
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Busdepot
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| Posted: Fri May 20, 2016 7:42 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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I will see if the supplier can give us an updated photo. I see you noted earlier that the ones you got from us had no problems with rubbing, unlike the ones other vendors have been selling, even if they differed slightly from the photo.
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kreemoweet
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Joined: March 13, 2008
Posts: 4145
Location: Seattle, WA
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| Posted: Fri May 20, 2016 8:03 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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Yes, no rubbing, even with original-length inner bearing spacers. I was surprised, because the clearance to the drum is very close, even on original German backing plates.
It's sort of a mystery to me why others are having problems. Small differences in drum dimensions, perhaps?
I would presume the "Genuine VW" bus backing plates others sell are all from the same source? No?
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Busdepot
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| Posted: Fri May 20, 2016 8:39 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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| Quote: |
| I would presume the "Genuine VW" bus backing plates others sell are all from the same source? No? |
Not necessarily. There is production from Germany (not much anymore when it comes to Buses), Brazil, Mexico, etc. Then there is Volkswagen Classic Parts in Germany (a division of VW), who will in some cases source an aftermarket part and sprinkle holy water on it and now it is an official VW part. (Often it's the same part I can get from the actual supplier for a lot less money.) Also some parts were intended for U.S. spec Buses and some for other markets - which doesn't matter in cases where the specs were identical anyway, but in other cases the part simply doesn't fit properly. I spend much of my time trying to identify those differences (usually succeeding, periodically failing). So it's entirely plausible that our "Genuine VW" part would fit and someone else's wouldn't. They were both genuine VW, but from different divisions of VW and/or intended for different markets. Then there is also the possibility of flat-out incorrect cross-reference data. For example even some of my best suppliers list certain Bus and Vanagon parts as interchanging when I know from experience that they don't. Sure, it may be a genuine VW part - but it's the wrong genuine VW part. An unsuspecting retailer may take their word for it and end up selling a part that fits poorly if at all.
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SGKent
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| Posted: Sat May 21, 2016 9:02 am Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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the backing plates sold most places are vanagon plates which is a 251 part number. They are designed for the newer spacers. If 211 plates are available and they match the originals they would have a different offset. The variance in part might explain why some folks end up with rubbing and some do not. Let me restate. The offset is different between the 211 (bay) and 251 (vanagon) back plates. FWIW I have ordered these from several different places and every single time someone has told me that sell the 211 version they have shipped me the 251 version. The two parts look almost identical and if you asked VW for the 211 part they would have substituted the 251 part. There is a mention of the difference in spacers in Bentley (image #3 below) and also the a factory manual supplement. I don't recall if I got any backing plates from Ron. I know he was out the first time I needed some back in 2009. IMHO if one buys a genuine plate it will be the 251 part so just plan on new spacers, machining the drums or hearing the rubbing until it wears thru the high spots in the 251 plate. VW did not need to make the 211 part once they changed production on spacers.
These are my photos so I know they are accurate. The part number VW uses for the old spacers and new spacers is the same part number however the dimensions changed. All the parts have the VW/Audi stamp on them. The new ones are thicker so there is less chance of collapsing. They are also longer so they move the drum farther out.
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kreemoweet
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SGKent
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Location: at the beach in Northern Wokistan
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| Posted: Sat May 21, 2016 1:39 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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There are different variants of the Vanagon 251 plate. Some are late for self adjusters etc. Those might be /D. The early ones have adjusting holes but they are still a 251 part number. The 211 part was replaced with a 251 part number. I can only tell you that I have purchased 2 sets of 71-79 backing plates with adjuster holes from two sources and all were genuine VW. They were all purchased as 211 parts and arrived with a 251 part number instead of 211. They rub. If one does a search they will find many threads where people who replace backing plates get rubbing. The fix is use the new spacer when the backing plate is replaced or machine the drum. Yes. real bay plates made back in the 1970's were different. My 1977 had no holes for shoe hold down springs for example. And, they did not rub but they were too rusty to use safely. It is my belief (I have no finite proof) that the early 251 stamping is sold as a 211 part today and the late 251 stamping is used as the self-adjuster plate. If someone has photos of a NEW 211 part for sale compared to the EARLY 251 part with adjuster holes please post the photos side by side.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).
George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."
Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice" |
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SGKent
Samba Member
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Posts: 42936
Location: at the beach in Northern Wokistan
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| Posted: Sat May 21, 2016 3:58 pm Post subject: Re: Brake drum rubbing (Grinding) on backing plate |
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I was thinking this thread while we were taking the dogs in to get their annual shots.
It is not any of our faults, none of us, that the replacement backing plates rub. No one here chose that. We can't say we are victims either but this all falls under VW's decisions to abandon the air cooled market so many years ago. 30 years ago, when we needed a set of backing plates, we would have either gone into a VW dealer ship and gotten the correct 211 bay ones, or the parts person would have told us we needed to also replace the spacers or the drums would rub. Or, maybe we would find a low miles wreck and pay for the backing plates on that one.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).
George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."
Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice" |
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