Not intending to be a tutorial or anything, plenty of those out there. Just a testimonial to the ease of this procedure, with a bit of planning and understanding.

Pictures:

Taking off the fluid reservoir is easy. I took a turkey baster (or a big syringe) and sucked out all the fluid I could from the reservior, made it less messy when removing it. Still, i put a few towels down the hole, so as to protect the paint and metal below. Take off the reservoir cap, move/disconnect any vacuum lines running across your work path, and disconnect the feed line to the clutch cylinder from the reservior. Then just pull straight up on the whole reservoir till it disconnects. Don't jerk it, try to be steady, I didn't even use a screwdriver. Just be steady, I worked from the fatter (felt like the stronger) end first. It pops off.



I used a 7/16th wrench to get the hard lines disconnected from the cylinder housing (two are disco'd in this pic, one more to go). I left the thingy on the end of the housing (as you will see in other pictures), and took it off after I got the bmc out of the car. Blew the thing out with air hose, then installed it on the new bmc.




Took a 13mm wrench (I know... mixing things up.. it's the tools I got) to the nuts on the bolts connecting the bmc to the booster housing. Yes, that's rusty. We are replacing the part because we suspect a leak. In this pic, one nut is removed, and the other is still on.

 

The aluminum one was the bmc that was in the car. The replacement (from 944online, thank you, took a bit but we got the right part and good communication) is the black iron one. Like I mentioned before I took off the thingy and put it on the new bmc (with a 3/4 wrench). I blew it out with an air hose to make sure it was clean and clear.


This is the seal we think is the cause of the leak. Also, there is a weatherstrip issue at the bottom of the windshield we need to fix, and I think it is responsible for small amounts of water getting into the brake fluid, as there was rust on the piston and spring (correct terminology?).


After putting the new bmc in the car, we realized that the hard lines connected at a slightly different angle than the old one. As I was trying to reconnect one of the lines, I stripped the threads a bit (). My landlord is a much better, much smarter, and much more resourceful mechanic than me and came to my rescue to fix the threads (next two pics). I learned a couple things here.

1. Loosely connecting the hard lines to the bmc before putting it into place and bolting it down made this a much easier job, than trying to put the bmc in, then connect the lines.

2. A triangle file and a jewelers loop can help you rethread a connection.

3. Small hands (in this case, belonging to my girlyfriend, the cars owner) can come in REAL handy when working on a 951.

The stripped thread



The landlord to the rescue!!

 

The girlfriend didn't just buy an awesome car she can drive and look good in, she's putting in the work and love to make it hers.

Small hands can stuff rags where big hands cannot.



Our garage

 

Wow I really like the last pic with the raised hood, work towel, tools, and manual.

The 951 looks good even under repair.

btw did you notice symptoms, is that why you replaced the cylinder? If so, what were they and were they remedied?

 

Interesting choice of "tools" in that last pic.

 

The brake pedal was squishier than we wanted, and it seemed to release pressure all on it's own. We would come to a stop, with the pedal pressed almost the full way to the floor. If we stayed on the brake pedal, the brakes would eventually let loose and we would roll. You could get the car to stop again with a 'pump' of the brakes (the amount of pressure felt with the pedal would fluctuate). We assumed it needed bleeding, took it to a mechanic, who said it was the BMC. They took 2 weeks to try and find the part, so my girlfriend called 944online and it took us 1 week to get the new BMC. I replaced the BMC, and we'll bleed the brakes today, and see if the problem is resolved.

I think the Porsche designers may have actually had mandate to make the car look good, even with the hood up, given you might be under there A LOT

Apologies. Removed inappropriate for RL content from the picture.

 

Ah yes, the bowl tool.

 

Thanks for sharing!

 

No problem Hope it helps a little, or at least provides a picture that might not have been available before.

Update: Bled the brakes, got a great pedal feel but no grab on the brakes. It was my first ever bleed (was really easy, I did a quick thread on it too), so I probably missed some air in the lines. We'll bleed again (like I said, was pretty easy) and see what happens.

 

Did you bench bleed the brake MC before you installed it?

The MC from 944online, it it the universal MC that fits both the ATE and Girling OEM MCs.

Thanks for the information.

J_AZ

 

Nope, didn't bench bleed anything. I assume that means I should have filled the BMC with some fluid and operated the piston to fill all the little nooks and crannies before installing it?

Will this cause lasting problems, that I can't solve with a brake bleed?

 

good story. nice that the GF was helping out.

 

Th new MC should have come with instructions. The BMC traps air:



Did you get the 944Online universal BMC?

J_AZ

 

Thank you for that. I did get the universal, I assume, though I saw no such paper with it. It looked like the purpose of that was to pump the cylinder and tap it to rid it of any trapped air, with some sort of kit.

Could this be done with the cylinder in car? The brake pedal should operate the piston right, so that would do the same as me pressing the piston with the bmc out of the car? If I tap the bmc to help the trapped air out, could this air not then be flushed out of the brake lines?

The bmc job was easy enough that i don't actually mind taking it all the way out if I need too, but is there a way to do it while the BMC is in car?

 

Yes, it may be possible to do it in the car.

To get the air bubble out of the BMC---IF you cannot get a good hard brake pedal...try using a Motive brake line bleeder first...

If unable to get a hard brake pedal,

You need to get 3 short hoses and connections to the BMC like the picture above shows.

You would have to jack the rear of the car up maybe 2 feet +- a couple of inches and put a small bubble level under the BMC until the BMC shows level.

Follow the instructions above to remove air and reinstall the lines.

You might want to call 944Online and ask for advice and parts if needed to bench bleed the BMC they sold you.

GL
J_AZ