So having now gotten my 1983 733i running (a combination of the wrong main relay, missing coil lead, the wrong ecu, and a bad OBC relay box, and bad fuel pump. It was a hair pulling experience) I will be moving on to the next big hurdle. The brakes.
The car was sitting for years before I got it and had several different owners try to get it running/work on it by the looks of things. The most glaring issue however is that there appears to be no brake fluid in it, none, and naturally the pedal just sinks to the floor with no resistance.
Now on cars previous I would of course assume that it had a leaky caliper or brake line. However this being a hydroboost car, I was wondering if there was any chance the fluid could have gone somewhere else or if there was anything else special I should be aware of.
Thanks
1983 BMW 733i My current project (or at least one of them)
2003 Volvo V70 5 Speed Current Daily Driver
1993 300TE 4Matic Project wagon -sold
1997 E290 Turbo Diesel Wagon -traded for above, an amazingly comfortable car to drive, great drivetrain, but the rust, oh my god the rust
1992 BMW 525i -traded in
1990 Silver 300TE -Sold Loved the wagon, hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold
probably not the boost and brake fluid are separate systems.
At this point, anything rubber should have been replaced at least twice to me.
That being said, start with replacing all of the low pressure return lines for the system. It specified ATF way back in the 80s, but I have used power steering oil and hydraulic oil of similar weight with no issues. Use what you want. There is also a filter in there you should run, but most vehicles on the street do not use one.
As you know, neglected brake systems kill master cylinders. My guess it leaked out of the rear seal... or a dead caliper, I have yet to see a leaky rubber hose (wheel seal... yep!). Many of us have done the E32 rear caliper and rotor upgrade from the V8/V12 cars. This puts a pair of vented rotors on the back and helps to minimize nose dive. Front is just stock four pot calipers and vented. You can pick up stainless braided hoses easily for these cars if you like that, I did.
Pad choice is like an oil thread. Run what you want. I have run organics on my old 735i and a few W126. I like ceramics now for less dust, recently slapped Porterfield R4S on my F350 to try out. Totally quiet and seem to pull the reigns in hard when needed. I would probably slap these on my next E23 pad change.
I make E23 parts.
09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
10/1984 745i
11/1984 745i
11/1984 735i (10:1-265/6)
Ford, MB, and GM round out the pack.
HitManX is of course discussing two different fluid systems. The hydroboost, using Dexron ATF a few high pressure hoses and a few more, generally smaller, low pressure return lines to the reservoir and the larger low pressure pump feed line. The other is the brake system, might as well do the clutch system, too, you did get lucky with a manual transmission? These are obviously brake fluid systems.
Whoops! Maybe I missed the main point of the thread. If so, sorry!
I make E23 parts.
09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
10/1984 745i
11/1984 745i
11/1984 735i (10:1-265/6)
Ford, MB, and GM round out the pack.
No manual transmission. Although I'm probably one of the few who prefers a slush box. It may get treated to a 4 speed auto at some point, but that's way down the line.
As for the leak. So on a traditional brake system a bad rear seal on the MC would fill the brake booster. I would imagine on these it would just dribble down the firewall? If so I would expect to see peeling paint/rust under it. I'll have to take a look.
I'll probably just fill it with brake fluid and see what happens. I was just curious if there were any known culprits with the system.
On a side note, is there a PDF of the owners manual for those cars somewhere?
e38.org/e23
Same on the auto, worn out manuals are a pain in the ass.
I make E23 parts.
09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
10/1984 745i
11/1984 745i
11/1984 735i (10:1-265/6)
Ford, MB, and GM round out the pack.
Had my master cylinder for my 82 733i rebuilt by Jay who I would highly recommend. See his link below. My car sat for 15 years and had to replace the "Brake Bomb" too. I rebuilt calipers and everything works great.
https://www.bimmerforums.com/forum/s...ng-Booster-SLS
@Red Imola M3
Thanks for the link. If I need a rebuild I'll look into him. Being in Canada however shipping tends to make these forum services unrealistic for me as shipping usually out costs the value of the part... if kits are available I might just do it myself.... is there a how to on the forum somewhere? I'd be curious.
@HitmanX
Thanks for the link, I usually try to avoid that site due to all the broken links... I'll go have a peak and troll through it though
1983 BMW 733i My current project (or at least one of them)
2003 Volvo V70 5 Speed Current Daily Driver
1993 300TE 4Matic Project wagon -sold
1997 E290 Turbo Diesel Wagon -traded for above, an amazingly comfortable car to drive, great drivetrain, but the rust, oh my god the rust
1992 BMW 525i -traded in
1990 Silver 300TE -Sold Loved the wagon, hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold
Jay is a good guy, he does my boosters and SLS pumps. I was unaware he does brake masters now too.
I make E23 parts.
09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
10/1984 745i
11/1984 745i
11/1984 735i (10:1-265/6)
Ford, MB, and GM round out the pack.
Fair enough, still I think I might give it a go myself. I think its within my wheel house. I notice rebuild kits are listed based on the metal used (either steel or Aluminium MC). Were these used interchangeably in our cars?
Also, is there a walkthrough for a MC rebuild on these? Just curious.
1983 BMW 733i My current project (or at least one of them)
2003 Volvo V70 5 Speed Current Daily Driver
1993 300TE 4Matic Project wagon -sold
1997 E290 Turbo Diesel Wagon -traded for above, an amazingly comfortable car to drive, great drivetrain, but the rust, oh my god the rust
1992 BMW 525i -traded in
1990 Silver 300TE -Sold Loved the wagon, hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold
bump for info
1983 BMW 733i My current project (or at least one of them)
2003 Volvo V70 5 Speed Current Daily Driver
1993 300TE 4Matic Project wagon -sold
1997 E290 Turbo Diesel Wagon -traded for above, an amazingly comfortable car to drive, great drivetrain, but the rust, oh my god the rust
1992 BMW 525i -traded in
1990 Silver 300TE -Sold Loved the wagon, hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold
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