BMW 4 piston caliper + spacer Q's

[MRMOPARMAN]

gday guys, just working out a big rotor + 4 piston caliper conversion for the front of me rolla. i went to pick a part and had a looksie at the old ovlov and BMW 4 piston calipers, and noticed they had 2 brake lines running to them.. im assuming 1 line for each 2 pistons?

i was wondering if they would work properly if you Teed off the normal front brake line and ran to both sides of the caliper, or maybe even blocking off 1 side, and drilling the caliper to let fluid from 1 side into 2??

atm im in the process of choosing a disc to suit, and was wondering what the maximum spacer size in between the stub and caliper mount would be likely accepted by engineers?

thanx, Cameron.

[dattoman1000]

BMW and Volvo calipers can be cross drilled to run a single inlet pipe

However they are a big heavy hunk of cast iron
I'd take a look at some S4 RX7 4 pots. Nice and light being alloy and very wide mount spacing. Making it quite easy to fabricate an adapter plate for mounting to the strut

If you decide cast iron is for you I can show you pics of where to drill the volvos

[MRMOPARMAN]

thanx for the quick reply, they are quite heavy arent they! i found the BMW calipers bolted straight up to the struts i wanted to use (corona xt130) and depending which disc i use, i wont need to use a spacer, or maybe up to 10mm. i can use a bigger disc than the hilux 4 pot/pug disc conversion thats more common, and did i mention they're easy to find and are freakin cheap!

the volvo calipers didnt fit the struts and are only marginally lighter than the bmw's so i was thinking it wouldnt be worth it.

you wouldnt happen to know the mount bolt spacing of the mazda caliper would ya? the XT130 struts are supposed to be 90mm apart.

cameron.

[dattoman1000]

Mazda spacing is big....... 120 or 130mm from memory
One of the Maz people here will happily tell us I'm sure

With such a wide spacing you just bolt a flat piece of 10-12mm plate or alloy between the mount lugs. Then drill the holes where you need them

http://dimequarterly.tierranet.com/pictures/album5/Graeme_Suckling_03.jpg

[Madhatr]

You can do what you said, we use them on the earlier bmw's a bit as a cheap upgrade over the stock items.

http://rd-motorsport.net/images/stories/technical/brakes/girling/Splitter.jpg

Split the single line before the caliper and use the stock inlets on the girling items. Saves having to find a second set of lines (and a master cylinder with extra outlets) or drilling.

Which bmw did you get the calipers from? the volvo items share the same mount spacing as some of them, so they should have fit if they came from a car which they could be used on.

[MRMOPARMAN]

thanx for the replies. ill probably go the BMW calipers for now, and i i get serious and go adjustable coilovers at a later date, the mazdas sound like the go.

i havent bought the calipers yet, but they are off an E21 525? it had an injected big six anyways. there was also some off a same vintage 7 series.. i assumed they would be the same.

[Madhatr]

323i if its an E21. The volvo calipers have the same mount spacing so they should bolt right on.

7 series is different :)

[MRMOPARMAN]

whoops, that should have been E12! yeah it was definately a 5 series..

[Belly_up]

E12 is the 4 piston jobbies, the E28 went back to sliding 2 piston calipers.

in case anyone else is looking at cars at the wreckers to scavenge bits, E12 520i with the injected M10 4cyl ran solid front discs and rear drums, and i know that the later 528i had 4 wheel discs, with larger ventilated discs up front, and thus wider calipers (same caliper with a spacer, so you could in theory convert the older ones across, but by all accounts once you split the caliper they never seal again...), and at some point between those two models they changed, but i don't know where. Also the same ATE calipers as contemporary 911's, and ferrari 328's.

on that note, if anyone comes across rear calipers for an E12 528, or rebuild parts for said caliper, can you let me know, i'm guessing they're pretty useless to anyone else.

[dattoman1000]

K599S maybe ?

[Belly_up]

part number for?

[dattoman1000]

I thought that was the part # for rubber kits for those rear calipers.......... but it was a late night guess

[Belly_up]

ahh ok, could well be, i just wasnt' sure what you were saying :)

any idea what the availability on them is like? i think i bought the last stock that repco had in australia (the box looked like it was the first repco branded box ever...).
I spoke to the Aus ATE distributor (i think) and the conversation was something along the lines of:
me: do you guys have rebuild kits for e12 rear calipers?
them: no
me: can you get them?
them: yes, they have to come from germany though.
me: cool, when do you next expect to get some in?
them: when we have enough demand to justify a shipment.
me: and when might that be?
them: no idea.
me: can i give you my details so you can keep track of the demand?
them: no.

[dattoman1000]

K599S
Contains
P4720 seals x 2 (43mm)
P4739 boot x 2
Also a P4756 retaining clip which you could always re-use
There is also an oring/channel seal where the halves join (this is not in the kit)

P4720 is a common seal
Its used in Landcruiser calipers. SO shouldn't be too hard to find. K1822S is a cruiser caliper kit that contains 4 of them.
P4739 boot is possibly going to be alittle harder to find.
I don't have a listing handy for what they are used on
Oring is I believe a 7x2mm metric Nitrile oring that we source from Bearing Services. Any decent bearing company could supply if the brake shop has nothing.

That might be them

If they are 38mm pistons thats a different animal of course

[MRMOPARMAN]

hey belly up, im pretty sure that E12 i was looking at still had the rear calipers on it.. ill be goin back this sat morning, ill have another look to make sure if ya want (while im grabbin the front calipers)

[Belly_up]

K599S
Contains
P4720 seals x 2 (43mm)
P4739 boot x 2
...


Thanks for that Dattoman, would be sweet if i can use landcruiser seals. It think i actually posted my piston sizes in some other thread around here, i'll have a search around and find out...


hey belly up, im pretty sure that E12 i was looking at still had the rear calipers on it.. ill be goin back this sat morning, ill have another look to make sure if ya want (while im grabbin the front calipers)


That's be sweet if you could have a look and find out what the wreckeers want for them, another set of calipers wouldn't go astray even if i get the current ones back together ok.

(oh and apologies for the thread hijack...)

Cheers

Adam

[Belly_up]

ok, apparently rears are 42mm dia pistons. not sure where i got that measurement from, i think it may have been from an ATE catalogue, not from the actual caliper. Is is possible a mm has been lost in translation somewhere?

[dattoman1000]

1 5/8" is 41.28mm these are P4712 seals
1 11/16" is 42.86mm these are the P4720

So its either stretch the P4712 or use the P4720
I'd go with the P4720 myself
It is the listed seal for that model

Neil

[MRMOPARMAN]

went to pick a part at broady today, theres 2 sets of rear E12 calipers there untouched. no fronts now tho :)

calipers are $26ea or $30ea with warranty

[jmac]

If I could hi-jack this a little - hey Dattoman - any chance you have some digi pics of the drillings on volvo calipers to enable the use of a single inlet pipe?

[dattoman1000]

http://i3.photobucket.com/albums/y83/dattoman/torana/outer.jpg
http://i3.photobucket.com/albums/y83/dattoman/torana/1.jpg
http://i3.photobucket.com/albums/y83/dattoman/torana/2.jpg
http://i3.photobucket.com/albums/y83/dattoman/torana/3.jpg

[jmac]

thankyou muchly