I installed front discs on my oval a few years back and was sent the M/C with the conversion kit. The front brake work great but I don't seem to get much if any stopping power from the rear when on the road. When jacked up the rears seem to stop fine but I'm not feeling them on the road. It will lock the fronts on a dirt road but nothing from the rear. They have been bled and adjusted and all new lines thru the whole car. Any ideas?
Thanks
Correct M/C for front disc conversion?
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surfbeetle
- Posts: 423
- Joined: Sun Apr 01, 2007 10:20 pm
Re: Correct M/C for front disc conversion?
Sounds like you need to add a proportioning valve into your system to be able to adjust it so there's more pressure at the rear. Another option is to just do discs on the rear, your post makes it sound like you only have front discs and rear drums. One other option for the rear is to convert it to type three rear drums.
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Marc
- Moderator
- Posts: 23741
- Joined: Thu May 23, 2002 12:01 am
Re: Correct M/C for front disc conversion?
Some European countries have stopping distance regulations indexed to vehicle speed, which necessitated fitting front discs to Beetles with 1500cc engines while the 1200 and 1300 models could still get away with drums. They used the Karmann-Ghia components, and with the lighter nose weight of the Beetle the higher front-to-rear bias was enough to promote earlier front lockup on wet pavement but it wasn't judged bad enough to warrant any other modifications.
The ubiquitous disc-brake conversion kits available for balljoint Beetles use `66-`71 Type III calipers, which are larger than the original K-G ones and result in even more of an imbalance when used with stock Beetle rear brakes, especially pre`68 "skinny-shoe" ones. Dunno what calipers you have (they may not even be VW) but it sounds like you've got the same issue.
I'm assuming you're running 5x205 rims and want to stay that way. Short of going with an aftermarket rear-disc conversion, the Type III drum setup would be the best choice IMO. The backingplates/shoes/cylinders/etc. could come from any mid`60s-up Type III or from a Type IV, but you probably wouldn't find any good-used wide-five drums so those'd have to be new repops. The drums are larger in both diameter and width but the effect on track width is minimal (<¼") so you shouldn't have any fender clearance problems.
Some stock master cylinders are equipped with residual-pressure check valves - those are fine with drums but cause drag & excessive pad wear with discs. I found that out the hard way many years ago when I put a `68 dual-circuit M/C into my Euro-spec `67 1500 Beetle
What master cylinder are you using?
The ubiquitous disc-brake conversion kits available for balljoint Beetles use `66-`71 Type III calipers, which are larger than the original K-G ones and result in even more of an imbalance when used with stock Beetle rear brakes, especially pre`68 "skinny-shoe" ones. Dunno what calipers you have (they may not even be VW) but it sounds like you've got the same issue.
I'm assuming you're running 5x205 rims and want to stay that way. Short of going with an aftermarket rear-disc conversion, the Type III drum setup would be the best choice IMO. The backingplates/shoes/cylinders/etc. could come from any mid`60s-up Type III or from a Type IV, but you probably wouldn't find any good-used wide-five drums so those'd have to be new repops. The drums are larger in both diameter and width but the effect on track width is minimal (<¼") so you shouldn't have any fender clearance problems.
Some stock master cylinders are equipped with residual-pressure check valves - those are fine with drums but cause drag & excessive pad wear with discs. I found that out the hard way many years ago when I put a `68 dual-circuit M/C into my Euro-spec `67 1500 Beetle
What master cylinder are you using?