Brembo brake conversion

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sideshowbob
Posts: 247
Joined: Mon Aug 01, 2011 2:18 pm
Location: Hampshire UK

Brembo brake conversion

Post by sideshowbob »

Have acquired a set of Brembo 4 pot calipers from an E38 7 series, having them sandblasted and repainted.

Will then rebuild them.

Have purchased some brackets from E28Goodies to fit them to my existing struts, car is running on 17" BBS RC090 wheels so clearance is not an issue.

Will also be fitting HEL braided reinforced hoses

Have been advised I need to fit a master cylinder from an E32 750 which is proving a bit problematical as I can't seem to source one either new or secondhand at a reasonable price. I only need the master cylinder as I think the servo unit and reservoir will fit from my existing unit, unless someone on here knows differently....open to advice.

My question is that my existing unit on my '88 636 looks very similar to the E32 750 unit, I appreciate there might be a slight difference in bore and stroke...again advice accepted. What would be the outcome if I did this conversion using my existing set up, ie. did not replace the 635 servo master cylinder unit .

Thanks in advance
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jps635
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Joined: Sat Feb 27, 2010 10:50 pm
Location: NZ

Re: Brembo brake conversion

Post by jps635 »

Have a read through this, may answer your question.
Attachments
Brake Upgrade Guide.pdf
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'85 635csi JPS (RA2-66)
sideshowbob
Posts: 247
Joined: Mon Aug 01, 2011 2:18 pm
Location: Hampshire UK

Re: Brembo brake conversion

Post by sideshowbob »

Thanks for that,

One final question does anyone know if the 635 CSi plastic brake fluid reservoir will directly fit onto the E32 750 brake master cylinder

Thanks
plip1953
Posts: 400
Joined: Mon Aug 13, 2018 4:15 pm
Location: Leeds

Re: Brembo brake conversion

Post by plip1953 »

I think I know a fair bit about brakes on a race car setup, but almost always that would involve a pedal box arrangement with twin master cylinders ie one exclusively for the fronts and the other for the rears.

In that kind of situation a change in brake calipers on one of the axles would naturally lead you to question, and potentially change, the internal bore size of the associated master cylinder. An increase in the overall caliper piston(s) area compared with the previous setup would require more fluid to be moved for any given mount of pad travel (giving a longer pedal), but increasing the master cylinder diameter to compensate for that would then mean more pedal effort required.

But with a dual master cylinder arrangement whatever you might do in terms of compensating for a change in front calipers would also have an effect (whether that be positive or negative) on the rear brakes.

It's worth bearing in mind that the amount of brake pad travel from when the disc is rotating freely to when the pad is fully in contact and under full pressure is actually (or should be ) only fractions of a millimetre. And therefore much of the actual brake pedal movement (as has alluded to in an earlier post) is down to expansion of rubber pipes, leaking seals, tired brake fluid or poor bleeding. Thus switching to metal braided flexi lines and making sure master cylinder internals are in good order is always a good thing, as is using fresh good quality fluid and bleeding very thoroughly.
Phil
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1988 Highline 635 CSi
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