Question about brake master cylinder

[Guts1200]

Sorry to make another thread but I wanted to be absolutely sure about this: can a 7 series master cylinder be used in a 1996 850? I've heard it can and that it cannot on the forum... can anyone give a definitive answer? Using the 7 series part would save me like $700 so... yeah.

Much appreciated,
Ash

[TxGR8White]

The E32 master cylinder only works on M70 cars, since the bolt holes are different at the booster, but otherwise it works just fine (for M70's)

[PabloRock]

Wrote this for the DIY section when I changed mine (a 1991). But like TxGR8 says, it could be different for anything but the M70 (plus I just noticed I have 666 posts, so I have to do one more so the devil doesn't come after my car).

https://www.bimmerforums.com/forum/s...BMW-850i-(e31)

[Guts1200]

Thank you guys, this forum is amazing

[Guts1200]

Is this the right part for a 1996?

https://www.fcpeuro.com/products/bmw...0i-34311160197

It says it works for all years?

[TxGR8White]

The early cars (M70) have a different bolt mounting pattern to the booster than the later (M73) cars. It will only work on one or the other. The later cars have the same bolt pattern as the 840’s.
The part number of the MC that you posted will only work on M70 & S70 engined cars (check the part number on realoem)

[cartoonz]

Trouble is.. .RealOem doesn't list the master cylinder at all for the later cars

IF it is indeed the same as the later 840's, The part number for the right one is 34311162914

But looking at the diagrams, it sure looks like 34311160197 does fit the M73 cars. You sure they are like the 840's?

[hemi4me]

I purchased an E32 Master cylinder from Rock Auto for about $100. As stated above it will only work with M70 cars (mine is an 1990 850i). I used PabloRock's procedure as a reference. Enerything worked like a charm and I noticed no difference in pedal pressure or braking performance....

[toomanyparts]

If both the master and booster are changed to an M70 version, can they be used in an 840?

[TxGR8White]

If both the master and booster are changed to an M70 version, can they be used in an 840?

The outgoing ports are slightly different. You would need to get the hardliners redone also.

[toomanyparts]

Thanks. Sounds like it is cheaper just rebuilding the booster and replacing the 840 specific MC.

[Guts1200]

Thanks guys. So this is the right one:

https://www.ecstuning.com/b-genuine-...r/34311162914/

[cartoonz]

Thanks guys. So this is the right one:

https://www.ecstuning.com/b-genuine-...r/34311162914/

That IS the right one for the 840's... I'd trust Steffen and order it for the M73
But considering it is rather pricey, take a close look at the one actually in your car. The other ones have mounting holes pretty much centered horizontally with the bore, the 840 ones look like the pic on ECS's site. There's enough of a difference to see

[TxGR8White]

840, if I remember correctly, has three mounting holes, 1 on each side and the third on the bottom. I highly recommend that you triple verify what you order from anyone other than the dealer. Buying a water pump years ago for an 850, turned out to be incorrect because the third parter vendor thought the 750 water pump is identical to the 850 ( both being mounted on the M70), this is not correct, as the 850 has an extra port for the overflow hose. Most of the E31 parts are specific to that model. Good luck and let us know how it turns out for you.

[mbarrett635]

Thanks guys. So this is the right one:

https://www.ecstuning.com/b-genuine-...r/34311162914/

This is the correct one for an M73 850Ci: https://www.ecstuning.com/b-genuine-...r/34311160197/

[Guts1200]

Sorry for the late reply... I've been sick the last few days and have been just laying around doing the bare minimum. Finally starting to feel better...

Mbarrett - I cant seem to get through to your link... it redirects to something called viglink and I'm unable to get past that to the ecstuning site. Am I doing something wrong?

I noticed that it says you own a 96 in your signature. Do you know that the brake master cylinder you're recommending is the correct item from experience?

[mbarrett635]

Sorry for the late reply... I've been sick the last few days and have been just laying around doing the bare minimum. Finally starting to feel better...

Mbarrett - I cant seem to get through to your link... it redirects to something called viglink and I'm unable to get past that to the ecstuning site. Am I doing something wrong?

I noticed that it says you own a 96 in your signature. Do you know that the brake master cylinder you're recommending is the correct item from experience?

ECS tuning sends you to an ad before you can see the actual item. When you click on the link in my post, look for the link that says "skip these deals & continue to ecstuning.com". That should take you to the part in question.

[cartoonz]

ECS tuning isn't doing that, Bimmerforums is...

[Guts1200]

Ha! I don't know how I missed that! Thanks!

So, that model # is the one I started with but txgr8white is saying it doesn't work for cars with a M73. Are you sure that's the right part? Have you used it before? If that one works, I should be able to use the 7 series part (I think).

PS - cartoonz, the fcpeuro link in this thread doesn't redirect like that

[shogun]

PS - cartoonz, the fcpeuro link in this thread doesn't redirect like that

this viglink is really disturbing, and difficult to escape. You can go to the viglink opt out site and click there opt out https://www.viglink.com/opt-out/ click disable. But sooner or later you will have to go there again and opt out, a never ending story. I tried adwcleaner, but it did not find anything.
some info https://www.2-spyware.com/remove-viglink.html

[Guts1200]

Since it seems like no one knows for sure, I think I'm just going to order the part that everyone has marked as working for my car. That way, if it doesn't fit, hopefully they will at least allow me to return it without penalty.

[toomanyparts]

Can you not read part no. from existing unit?

[mbarrett635]

I’m sorry it’s taken me so long to respond to this, but I’ve been away from my car and couldn’t check. However last night I checked my 96 M73, and it’s definitely a three bolt master cylinder, which is the same as the 840 master cylinder I believe, but is definitely not the same as the M70 version; nor is it the same one as shown as applicable to all 850s on the ECS website. Their information in that regard is incorrect.


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[Guts1200]

Thank you for checking Mike. I called BMW (probably what I should've done from the get-go) and they said this is the correct part #:

34331161950

They looked it up based on my vin so it should be right. Most websites also show that it fits 840s and late model 850s. Found it at BMW of Cincinnati for $824.

Edit: made a mistake, this part # is actually for the brake booster.

[toomanyparts]

The ETK is wrong sometimes as well (see PS filter for later cars).