Brake Booster Removal

threesticks · 09-14-2001, 04:05 PM

I'm going to have to replace the vacuum brake booster in my '86 951. The brake pedal takes a lot of effort to stop the car. The booster gets and holds vacuum and the brake fluid is recent and is holding.
I pumped the brake pedal several times with the engine off to bleed off the vacuum in the booster and applied moderate pressure to the brake pedal and started the engine and the pedal had almost no movement.
Has anyone replaced the booster on their 951 that could give me some pointers and some advice or does anyone know where I can find the procedure on the net?
There sure is alot of stuff around the booster and any help would be greatly appreaciated.
Thanks, Threesticks.

javier · 09-14-2001, 04:53 PM

b b b b bump

TroyN · 07-18-2011, 08:34 PM

How's this for a 10-year-old bump? I've searched and searched, is there a good DIY out there somewhere?

So far I have the under-dash booster bolts out, and the master cylinder is detached and can't pull the booster out.

Hopefully this time around, there are some useful replies to this thread...

TroyN · 07-18-2011, 08:35 PM

How's this for a 10-year-old bump? I've searched and searched, is there a good DIY out there somewhere?

So far I have the under-dash booster bolts out, and the master cylinder is detached and can't pull the booster out.

Hopefully this time around, there are some useful replies to this thread...

MrTibbs · MrTibbs's Garage

Your car's probably has the fuel lines in a different place from my 924S, but on mine the fuel hard lines trap the booster adapter on the firewall. To remove the booster you have to lever one of the plastic clips that holds the lines to the firewall off and bend the lines out of the way.

Mike

TroyN · 07-19-2011, 05:42 AM

Thanks Mike, it's really the brake heat shield that is the problem. It looks like you can't get the heat shield out with the booster there and can't get the booster out w/ the heat shield there!

mikepellegrini · mikepellegrini's Garage

Yeah, the heat shield is the key. If I remember correctly, there are three bolts on the bottom and about the same number along the top.

I have a spare heat shield. When I get home from work tonight, I'll take a picture of it and post it so you can see the locations of the bolts. Some of the bolts were a real major PITA for me to get out.

I also had issues with vacuum hoses under the intake manifold and so I took that off as well - and it did make it easier to get at some of the heat shield bolts.

I also removed the dipstick.

Before you remove the master cylinder, get as much brake fluid out as you can - I used a turkey baster.

Then when you get the heat shield finally off, undo your brake and clutch lines at the master cylinder.

The reservoir just pops off the master cylinder. I used a small crowbar and gently pried it off.

Once you have the reservoir off, then there are two 13mm nuts that hold the master cylinder to the booster.

Voila!

Once off, keep the master cylinder as flat as possible so you don't spill brake fluid out. If you manage to keep it full, it'll make it a lot easier to bleed later.

mikepellegrini · mikepellegrini's Garage

Here's a picture. This is off an 87, and has only 5 attachments - I could have been wrong about the number on my 86 (it seemed like 100 bolts, the amount of time I spent struggling with it).