Audi 100 Coupé S brake booster

Jaco Mostert · 29-08-14, 03:07 PM

Hi,

I'm looking for a replacement brake booster for my Coupé S. Apparently it has the same brake booster as a 1100 Mk1 golf, which is 9 inch in diameter. According to the sales assistant at the parts store where I usually get all my parts this brake booster is no longer manufactured and i can only get the newer 10 inch brake booster. I'll have to modify the pipelines and get a new master cylinder to use the 10 inch brake booster.

Will I have to do this or is there another brake booster that fits my car without a lot of modifications?

Stanson · 29-08-14, 08:45 PM

Quote:

Originally Posted by Jaco Mostert

Hi,

I'm looking for a replacement brake booster for my Coupé S. Apparently it has the same brake booster as a 1100 Mk1 golf, which is 9 inch in diameter. According to the sales assistant at the parts store where I usually get all my parts this brake booster is no longer manufactured and i can only get the newer 10 inch brake booster. I'll have to modify the pipelines and get a new master cylinder to use the 10 inch brake booster.

Will I have to do this or is there another brake booster that fits my car without a lot of modifications?

I have Audi A8 D2 8"/7" two-membrane booster + master cylinder in my 100/44. Fits perfeclty, but you have to use 2 T-fittings, because A8 master cylinder have only two outputs. May be you will have to make something with push rod to fit to your pedal, but that's easy if you have access to lathe. AFAIK, all Classic Audis have standard 4-hole mounting for the booster, and A8 booster perfectly fit with it's 2 bolts into standard holes.

Also, take a look at A6/A4 boosters/master cylinders, they are slightly weaker than A8 (however, they still much more powerful than classic booster) but have the same sizes.

Brakes are fantastic with A8 booster on my 100/44. I also will put A8 booster into my wife's Coupe B2 soon.

Just a picture of how it's look like:

This is A8 booster/cylinder on A100

Jaco Mostert · 01-09-14, 04:34 PM

Thanks for the reply, I'll see where I can get one of those, my C4 A6 just took my savings after blowing the head gaskets the past weekend. Luckily only the gaskets got damaged and I'm replacing them this weekend.

Jaco Mostert · 13-04-17, 09:05 PM

Sorry for resurrecting this thread, but I might be able to help someone out.

I found a suitable brake booster for my car. Turns out the Porsche 944's booster fits almost perfectly. With the stock brake booster the brake pedal sits a bit low, but the brakes feel great. Extending the rod that goes into the booster should solve this.

Hope my image is added. I'm a bit rusty.

13-04-17, 09:05 PM	#4
Jaco Mostert Grown up member Join Date: Dec 2013 Location: South-Africa, Hartbeespoort Posts: 49	Solution Sorry for resurrecting this thread, but I might be able to help someone out. I found a suitable brake booster for my car. Turns out the Porsche 944's booster fits almost perfectly. With the stock brake booster the brake pedal sits a bit low, but the brakes feel great. Extending the rod that goes into the booster should solve this. Hope my image is added. I'm a bit rusty.

01-09-14, 04:34 PM	#3
Jaco Mostert Grown up member Join Date: Dec 2013 Location: South-Africa, Hartbeespoort Posts: 49	Thanks for the reply, I'll see where I can get one of those, my C4 A6 just took my savings after blowing the head gaskets the past weekend. Luckily only the gaskets got damaged and I'm replacing them this weekend.