BMW calipers Options

[mike_the_man]

Hi all,

I just bought some calipers from an early 80's BMW 320i for the teener. I've heard that they have to be machined slightly to fit. Does anybody know how much material has to be taken off, or the best way to measure how much to remove? They will be going on to a 74 2.0L. I haven't tried to install them yet, but I'm assuming that the mounting ears need to be machined down a little so that the rotor is perfectly centered in the caliper, correct?

[rick 918-S]

Someone has done this here that's for sure. I guess the pads also ride slightly high on the rotor.

[john rogers]

The "other 914 site" has the article that covers how to machine the mounting bosses. The biggest problem is they have to be parallel to each other and to the rotation of the rotor. Most machine shops can easily jig them up.

[skline]

They need to be machined down about 1/8 of an inch to fit on 73 and up cars. The Vovlo caliper is the one that rides high on the rotor, the 320i brakes are fine.

[Dave Blackburn]

I machined mine down about 1/8". The exact number can be found with a micrometer.
I used a grinder to grind the ears down, then I used a very large, flat file to finish the job.
I ended up with the ears within +/- 0.001". It toook me about an hour to do both. They work great!
Good luck.
Dave (IMG:style_emoticons/default/beerchug.gif)

[Aaron Cox]

do any late model 3 series/5 series have a 914 compatible caliper that is vented?

scott... how did you solve the volvo issue.....redrill mounting holes?

[Mueller]

I spoke with an engineer at Wilwood, he said a little overhang is no big deal, not sure how much you get with the Volvo calipers...the biggest issue is to make sure that you change your pads before they could ever get to the point of contacting each other due to the overhang of the pads and the narrowing of the rotor.....in fact the Winston Cup car at Brads old shop had about 1/4" to 3/8" worth of overhang on it's massive brakes.
This was an ex-roush or one of those big name, big dollar cars, not some garage built contraption

of course too much overhang and you start to loose the advantage of going to a caliper with more surface area for the pads.

[skline]

Didnt really solve it, just going to run them tomporarily till I get the M calipers rebuilt. The just ride a little high on the rotor. I could slot the holes but I dont want to modify them. I am thinking about changing to later model struts to run the really big brembo calipers on the front and then run the Vovlos on the rear with a Renegade rear E brake system. As far as the later BMW brakes, no, none of them will directly fit our cars without major modifications as far as I know.

[rick 918-S]

I'm running 4 piston units from a BMW 2002. They are much lighter than the Volvo. (unsprung wieght is not our friend) Also I think they would cause less heat build up and possible warping of the rotors. Just my oppinion. But what do I know.

[banderson]

I did this last year. If I were to do it again now, I would seriously consider the new hubs. Vented rotors are the way to go. BMW will not get rid of heat any faster.

Anyway, the trick to machining the rotors is holding them. The holes can be taped to 1/2-20 and a block of AL can be drilled with the correct spacing and screwed to the back side of the caliper. Then it can be held in a vise and machined.

[SteveSr]

Also have read that pre 73 cars require no machining at all..........? (IMG:style_emoticons/default/sawzall-smiley.gif)

SteveSr

[Aaron Cox]

I'm running 4 piston units from a BMW 2002. They are much lighter than the Volvo. (unsprung wieght is not our friend) Also I think they would cause less heat build up and possible warping of the rotors. Just my oppinion. But what do I know.

i rebuilt my friends 2002 calipers for his '02. it'd be great if there could be a spacer for the caliper, to make it for a vented rotor