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metahacker Samba Member
Joined: May 26, 2010 Posts: 691 Location: san.diego
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Posted: Sat Sep 18, 2021 7:51 am Post subject: Aluminum rear brake drum |
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Has anyone ever been bold (and clever) enough to equip a Bay window with aluminum rear drums?
Has anyone ever seen custom made aluminum drums?
I do not believe that a CNC rear drum "blank" would be a difficult endeavor for the Late Bay (particularly given the fact that they do not need to hold any lug bolts directly)... but I believe a finished rear drum poses a significant challenge in terms of mounting the friction surface.
How did Porsche do it on the 356A? I have to doubt that the friction area inserts were simply press-fit.
I know SGKent will tell me to buy an Acura SUV with 350HP for asking this, but hey, inquiring minds want to know |
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TDCTDI Samba Advocatus Diaboli
Joined: August 31, 2013 Posts: 12819 Location: North Carolina
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Posted: Sat Sep 18, 2021 8:27 am Post subject: Re: Aluminum rear brake drum |
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It’d be simpler, cheaper, & more effective to convert to disc. _________________ Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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mikewire Samba Member
Joined: March 22, 2010 Posts: 802 Location: San Antonio, TX
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Sep 18, 2021 10:37 am Post subject: Re: Aluminum rear brake drum |
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aluminum would gall. One would have to put a steel sleeve in it and eventually it would come loose. I can see the racing example because everything is being changed after a few races. Even a tire that has rubber left gets hard and looses its gummy grip so those get changed on cars that don't do a lot of laps. The trick set up would be to put a disk caliper system on the transmission to brake the rear wheels. That reduces rotational mass and unsprung weight. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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TomWesty Samba Member
Joined: November 23, 2007 Posts: 3482 Location: Wyoming,USA
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Posted: Sat Sep 18, 2021 11:41 am Post subject: Re: Aluminum rear brake drum |
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SGKent wrote: |
aluminum would gall. One would have to put a steel sleeve in it and eventually it would come loose. I can see the racing example because everything is being changed after a few races. Even a tire that has rubber left gets hard and looses its gummy grip so those get changed on cars that don't do a lot of laps. The trick set up would be to put a disk caliper system on the transmission to brake the rear wheels. That reduces rotational mass and unsprung weight. |
Or get an Acura SUV! _________________ If you haven't bled on them, you haven't worked on them.
Visit: www.tomcoryell.com and check out my music! |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Sep 18, 2021 3:10 pm Post subject: Re: Aluminum rear brake drum |
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TomWesty wrote: |
SGKent wrote: |
aluminum would gall. One would have to put a steel sleeve in it and eventually it would come loose. I can see the racing example because everything is being changed after a few races. Even a tire that has rubber left gets hard and looses its gummy grip so those get changed on cars that don't do a lot of laps. The trick set up would be to put a disk caliper system on the transmission to brake the rear wheels. That reduces rotational mass and unsprung weight. |
Or get an Acura SUV! |
True, that is how we get around when all but cruising in the VW or camping - but you knew that already. We also use the 04 Sable wagon sometimes. If someone wants to beef up brakes in a bay, maybe a set of 944 brakes might be a solution. That said, I had to make a panic stop in my bus right after I restored it to avoid a red light runner, and from about 35 mph it stopped in just over a bus length. The distance buses stop in is very short unless they have a heavy load. The limit is more the tires grip than the brakes. The engineering payload in a bus is 2000 lbs so the brakes are overkill. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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Cap10323 Samba Member
Joined: July 24, 2016 Posts: 604 Location: Ohio
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Posted: Sat Sep 18, 2021 8:34 pm Post subject: Re: Aluminum rear brake drum |
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SGKent wrote: |
The distance buses stop in is very short unless they have a heavy load. The limit is more the tires grip than the brakes. The engineering payload in a bus is 2000 lbs so the brakes are overkill. |
I was going to say. Providing your brakes are in good shape, the stock brake setup in a bay window is really pretty damn good.
My 77 Bus, even with full camper interior, panic-stops in about a bus and a half's worth of length. All 4 tires locked. It almost outstops my other car, which is a 2005 Subaru wagon. _________________ -Ian
'77 Westfalia - 2.0 F.I |
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mikedjames Samba Member
Joined: July 02, 2012 Posts: 2715 Location: Hamble, Hampshire, UK
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Posted: Sun Sep 19, 2021 3:18 am Post subject: Re: Aluminum rear brake drum |
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Even without a servo in a European bus over here, I have stopped from 60mph faster than a modern GM car.. They hit my towbar and suffered more damage than my bus. They almost stopped in the same distance.
And having warped a set of cast iron drums through heat, I would not want to use aluminum with its lower softening temperature. _________________ Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy |
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Starbucket Samba Member
Joined: April 30, 2007 Posts: 4007 Location: WA
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Posted: Sun Sep 19, 2021 2:27 pm Post subject: Re: Aluminum rear brake drum |
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Let's see: You would need a mold to cast a donut with an outer rib, have a foundry cast it in iron, then have it machined to apx. size with the outer surface finished with a dove tail in the outer rib, then have a mold made to cast the aluminum around it and then have it finished machined, an order of 100 would only cost you around $2000. ea. if you are lucky. (and a set of 2 will only save you 1lb.) |
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metahacker Samba Member
Joined: May 26, 2010 Posts: 691 Location: san.diego
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Posted: Mon Sep 20, 2021 7:11 pm Post subject: Re: Aluminum rear brake drum |
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Hmm, I have seen 356B drums on barndoors.. so I assumed someone had been brave enough to figure this out on some other VWs.
I know that there are many OE aluminum drums (perhaps most famously the GM ones...such as used on Buicks...and Corvair...), so I'd imagine it might be possible to machine one down to fit a late bay VW Bus rear.
I also think making a blank from scratch also seems reasonable given the relatively easy access to CAD/CNC machining that individuals enjoy in "modern times." But, again, not so sure how one could effectively mount a friction surface. It seems a bit challenging. I assume one could machine down a stock iron drum and use the inner ring as a friction surface, and attach the aluminum outer drum using fasteners anywhere where wear from the brake shoes won't cause them to fail. Maybe not the most sophisticated way to do it, though.
Sure would be nice if there was something off the shelf that cross referenced (e.g. Porsche 356 or Corvair) closely enough that it just required drilling new holes for the studs.
I will refrain from "convincing" anyone why they are "needed." Needless to say, they would perform better than stock and make a not insignificant reduction to unsprung weight/ rotational mass. And yes, SGKent, I agree, inboard brakes would be the ultimate |
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