Hi, maybe I'm over-complicating things, but it seems there's some conflicting info floating around about E32 master cylinders. In an attempt to get to the bottom of it, here's what I've found (feel free to correct me on anything you think is wrong)
750i upgrade for stock E30
The E32 750i/iL master cylinder* from ATE is 34311156643. By coincidence, this master cyl bolts up to an E30 booster. Doing this improves the pedal firmness, I used to have this and it was fantastic. This master cylinder was also used on the 735i until 03/88.
* Although it is confusing because realoem also indicates some 750i's used a hydraulic system (using the power steering pump instead of vacuum). The "brake servo" for this is 34331161772, I haven't tried but I strongly suspect it isn't compatible with the E30 booster. Regardless, 34311156643 is the only "E32 750i brake master cylinder".
E32 master cyls for E30 DOHC swaps
Let's start with the master cyl, cos the booster situation is even more complicated! In 03/1988, the 735i changed from a hydraulic brake servo to a vacuum booster. The accompanying master cylinder, Lucas/Girling/TRW (same company) 34331156978, has been used on many E30 DOHC swaps (although a remote reservoir is often needed). This master cylinder is also used on some E34s.
E32 boosters for E30 DOHC swaps
The E32 735i/iL used two brake boosters:
- 34331160625 until 03/1990 (also used on some E34s, however the E34 may not have the spacer tube to move offset the booster from the firewall)
- 34331161486 from 03/1990 (also used in the E30 325iX)
I'm not sure what the difference is between these boosters, but the same master cylinder was used with both, so they are both compatible (my unfounded theory: perhaps the later one was slightly smaller, for packaging reasons in the 325iX)
Master cylinders for 944 boosters
My DOHC E30 currently uses the E30 master cyl with the 944 booster. The pedal feel is spongey IMHO (like stock E30) and I don't like it at all.
The 750i master cyl bolts up to the 944 booster fine and gives a good pedal feel (like it did with the E30 booster before the engine swap). But the force required to lock the wheels would have me bending brake pedals! This is very strange, given that it worked fine with the E30 booster and the E30 master cyl works fine with both boosters. Perhaps the reduced vacuum is killing it (although the reduced assistance isn't noticeable using the E30 master cyl, hmmmm strange).
So I will be trying a matching 735 booster and master cyl, to see if this improves the pedal feel. I'll update this post with how it goes.
Thanks to moatilliatta, for this parts list, it was a huge help.
750i upgrade for stock E30
The E32 750i/iL master cylinder* from ATE is 34311156643. By coincidence, this master cyl bolts up to an E30 booster. Doing this improves the pedal firmness, I used to have this and it was fantastic. This master cylinder was also used on the 735i until 03/88.
* Although it is confusing because realoem also indicates some 750i's used a hydraulic system (using the power steering pump instead of vacuum). The "brake servo" for this is 34331161772, I haven't tried but I strongly suspect it isn't compatible with the E30 booster. Regardless, 34311156643 is the only "E32 750i brake master cylinder".
E32 master cyls for E30 DOHC swaps
Let's start with the master cyl, cos the booster situation is even more complicated! In 03/1988, the 735i changed from a hydraulic brake servo to a vacuum booster. The accompanying master cylinder, Lucas/Girling/TRW (same company) 34331156978, has been used on many E30 DOHC swaps (although a remote reservoir is often needed). This master cylinder is also used on some E34s.
E32 boosters for E30 DOHC swaps
The E32 735i/iL used two brake boosters:
- 34331160625 until 03/1990 (also used on some E34s, however the E34 may not have the spacer tube to move offset the booster from the firewall)
- 34331161486 from 03/1990 (also used in the E30 325iX)
I'm not sure what the difference is between these boosters, but the same master cylinder was used with both, so they are both compatible (my unfounded theory: perhaps the later one was slightly smaller, for packaging reasons in the 325iX)
Master cylinders for 944 boosters
My DOHC E30 currently uses the E30 master cyl with the 944 booster. The pedal feel is spongey IMHO (like stock E30) and I don't like it at all.
The 750i master cyl bolts up to the 944 booster fine and gives a good pedal feel (like it did with the E30 booster before the engine swap). But the force required to lock the wheels would have me bending brake pedals! This is very strange, given that it worked fine with the E30 booster and the E30 master cyl works fine with both boosters. Perhaps the reduced vacuum is killing it (although the reduced assistance isn't noticeable using the E30 master cyl, hmmmm strange).
So I will be trying a matching 735 booster and master cyl, to see if this improves the pedal feel. I'll update this post with how it goes.
Thanks to moatilliatta, for this parts list, it was a huge help.
So confusing
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