E30 M50 swap with E90 booster

[digger]

I built a simple reservoir mounting bracket utilizing the power steering reservoir bracket where it bolts into the strut tower. Keeps the run to the master cylinder short and the clutch line hooks up nicely. My brake lines look lame, I know.

Where did you get the plastic fitting for the remote reservoir?

[Panici]

More info on the X3 booster if anyone is interested. I used a chase bays brake line relocation kit, rear proportioning valve, and thread adapters from eBay (Brake Hoses Unlimited - Male M12x1 bubble to Female M10x1 bubble).

It feels like a more modern car, without feeling numb. A little more boost for less travel and more positive engagement.
Can still threshold brake without ABS just fine.

Excerpts from my build thread:

Post 262:

To fix the 24v brake booster clearance issue, I went with an E83 X3 Brake booster & master cylinder.
From what I found online, this is supposed to be identical to the E90 booster & master, but with the hardline outputs on the correct side.

I thought this would be an almost plug-and-play solution, with just the clevis modification needed.
However I ended up having to slot the firewall (BCD of X3 booster is smaller), and remove the entire pedalbox to modify for hardware clearance.
(2022 EDIT: See Post 352, you don't have to slot the firewall.)

Post 266:

• Installed the Chase Bays Brake Line Relocation Kit.
  • Used thread adapters from "Brake Hoses Unlimited" on eBay. Details in image attached to this post.
  • Happy to report it looks like it will work with the X3 booster & master cyl.
  • Waiting to tighten up the connections at the booster until after everything else in that area is sorted.

Post 352

The other small project was shortening the rod for the X3 brake booster. I removed the silver plate from the back of the booster, so it should fit a bit nicer in the engine bay.
I didn't know this was removable when I installed the booster originally, as then I wouldn't have had to slot the mounting holes on the firewall. No matter, I made some patch pieces for the slotted holes and welded them up (X3 booster has only two mounting studs).

I shortened the rod on the booster a little extra to lower the brake pedal, which should make heel-toe downshifting easier.
Don't mind the blob of weld, I didn't bother cleaning it up (I had the wire speed a bit high). Worry not, the 240v welder was cranked up to full power and there was plenty of penetration.

[litu]

This is the last bit of info I have, this is the diagram of ABS lines, I have highlighted the green and red lines from my discussion above if this helps. I could NOT find an explanation anywhere of what these 5 lines are dedicated for.....

Sorry for late answer, but i will try to help...When looking that e90 booster pic where is that star and triangle and compare/looking this e30 abd brake line pic, so to me they go like this

-5=front left
-4=front right
-3=rear, first there is that pressure valve system, it is critical to have

So 2/red should go e90 to star and 1/green should go e90 triangle

[Buff_e30]

Cubby Chowder it looks like you have the ABS lines like I do and I dont know which lines to hook up to which ports on the e90 master.I have an '87 and I have an ABS system and lines still in place PLUS my lines were connected to like some stock proportioning valve.

^^So this is what came in my car The green circle in the below pic was connected to the green arrow in the above pic, red circle to the red arrow....

^^Here is the e90 booster in the car now with the unconnected brake lines from the ABS unit

OK, so I'm ASSUMING i will connect red circle to triangle OR star and connect green cirlce to triangle OR star. Someone help me please! I have line extensions and adapters ready i just need to know what goes where. THANK YOU!


This is the last bit of info I have, this is the diagram of ABS lines, I have highlighted the green and red lines from my discussion above if this helps. I could NOT find an explanation anywhere of what these 5 lines are dedicated for.....

[CubbyChowder]

I built a simple reservoir mounting bracket utilizing the power steering reservoir bracket where it bolts into the strut tower. Keeps the run to the master cylinder short and the clutch line hooks up nicely. My brake lines look lame, I know.

[Panici]

E83 X3 Booster & Master, 2002 Res, Chase Bays brakeline relocation kit.

Works with M50 & M52 manifolds.

[Buff_e30]

If I still have ABS in my car, will that affect which lines I connect to my e90 booster? do I still need the 'tee" for the front lines? I'm confused on which lines from my car connect to this e90 booster. I feel like I got brake lines everywhere!

[hoveringuy]

For the clevis I simply measured the firewall to clevis distance on the stock e30 booster, and cut the ears off the e90 rod, and got the length correct on the old e30 “fork” and welded it into the e90 pushrod

I like that much better than welding the entire e30 clevis, it keeps the heat away from the booster.

[bimmer630]

For the clevis I simply measured the firewall to clevis distance on the stock e30 booster, and cut the ears off the e90 rod, and got the length correct on the old e30 “fork” and welded it into the e90 pushrod

[bimmer630]

More pics. The forum is a pain in the arse for uploading pics. I stopped updating my build thread due to the pics never uploading correctly directly from my phone

[bimmer630]

I went with the E90 booster, But wanted to try the F10 reservoir just for cleaner looks, compared to the 2002 reservoir.
I ran into issues with the M50 TPS hitting the reservoir.. So I got an M52 throttle which cleared the bottle, but the throttle cables hit the master.
Picked up a RHD master from Europe.. made new brake lines..
Now that all fits, but I realized the OBD1 cruise control cables dont work on the OBD2 throttle. I cut the rigid end off of it, and took the same amount of length off of the outer sheathing to compensate, and then "swaged over" the remaining rigid end after putting the "Tee" part back on. Seems to work.
I did see a post or two on here about people modifying the servo end to make the obd2 cable work.. But I wanted to try it this way.

[hoveringuy]

64mm for 1150988 (or 34331150988)

Can't find the stock E30 one that I sat aside for this measurement, but I'll edit this post if it appears.

Measured my stock one to 44mm, so it's 20mm longer. Das stimmt.

I just added 5mm on to mine by cutting most of the stock threaded part off and gluing a section of 10mm hex coupling in place, added 5mm. Brake pedal now sits perfectly even with the clutch. An extra 20mm seems like way too much!

50mm would be about perfect, IMO.

[Northern]

64mm for 1150988 (or 34331150988)
I guess this is E24/E28 M30 cars with hydroboost. Realoem lists it under several NA spec cars, but the dealer says it's Euro only...
I had to order it from Lithuania because the local dealer told me to pound sand.
Can't find the stock E30 one that I sat aside for this measurement, but I'll edit this post if it appears.

[hoveringuy]

I've been meaning to take a comparison now that it's here. I'll try to do that tonight.

Cool. My short-term solution is that I'm gong to use a stock e30 clevis, cut the threaded portion off and weld on a longer M10 coupler (think nut that's 30cm long). It will give me a longer threaded portion.

[Northern]

I cut the E90 clevis off, threaded to e30 and used the E30 clevis, but it's not quite long enough and the brake pedal sits a hair too low.
I've also ordered the 6 series one and it's backordered for at least another month.
How much longer is that one? (E30 is 44mm?)

I've been meaning to take a comparison now that it's here. I'll try to do that tonight.