springer3

Stronger is not always better in mechanical design. Shear pins are, in many cases, the weak link by design - they shear to protect more expensive parts should something jam. Roll pins have some flex and cushion the bore. A grade 8 bolt is harder than carbon steel, and will deform the bore. I do not know the basis for the design in this case, but will always consider carefully before changing a factory design. I have seen a case where a well-intentioned change from a roll pin caused expensive harm. You should be fine with the bolt modification, but I am not sure it should be a recommended modification. A roll pin is cheaper and could be better. My roll pin may fail today for all I know, and I will have a good laugh when I read this again.

strost

Another, but context related question:

Does anybody know a purchasing source for this ?? dirt hose (yellow circled)? Mine is not ok, and as I heard, this is not a part to be sold by Porsche dealers.

Rocket Rob

That rubber boot comes with the clutch master cylinder (#1) in the drawing below. The part number is 993-423-171-00 (-92) and 993-423-149-00 (93+)

strost

Hi Rob,

Thx BUT: buy a new clutch master cylinder just 'cause the broken rubber??

What I meant with my post is that the RUBBER is not a single part to be sold by Porsche. I heard it is a part from ATE which is suppplier for all kind of hydraulic components in automotive.

So I look for a replacement only of the rubber boot ...

Thx

Rocket Rob

I agree that would be an overly expensive fix. Good luck in finding an alternate solution.

elbeee964

Best inexpensive source would be off a wreck.
Look into dismantlers. dCAutomotive comes to mind.

As an interior part, I'm less worried about a torn boot than on an exterior part, (i.e., the slave cyclinder.)

strost

Loonie - but anyway, my "hanging clutch pedal problem" is not longer hanging due to a bath with WD40. So there seems to an influence in interior, too!

@ all - IF I succeed in finding a substitute for the rubber I'll let you know.

elbeee964

heehee - "Loonie".

(That pretty much describes me on my busier days at work.)

Good luck with the search!

Richard Curtis

Looks close to a steering rack boot... do some measurements. Steering rack boots are generally available for a variety of cars. IIRC, last one I bought was about $10 U.S.

HiWind

another related question ... I moved this boot around last week while cleaning around the pedals.
Today I had the soft clutch/no ability to shift problem after some track time ... could I have broken a seal beneath the boot
or somehow introduced dirt/air into the system?

Also how do I get to the slave to bleed it? I don't have a motive (yet) but do have an (somewhat) willing assistant

Rocket Rob

The rubber boot on the clutch master is just a dust shield. Moving it won't cause air to enter the system. How to bleed it? Use a pressure bleeder like a Motiv. Its my understanding that you can't do it without a pressure bleeder.

How do you get to the slave to bleed it? The way I do it, is jack up the rear of the car, put it on jack stands, remove the left rear wheel. Attach your pressure bleeder to the brake fluid reservior, remembering to pinch off the vent. Pressurize the Motiv. Then slide under the car and put on a 7mm box wrench on the bleed nipple of the slave, attach a bleed hose. Open the bleed screw to start bleeding. The tricky part is you can't see what you are doing but once you feel the slave, the bleed nipple is easy to find. To find the slave, have your hand follow the rubber hose that leads to it.

HiWind

cheers Rob - all the answers I could need - as always very generous with your time! Thanks!
I was thinking of trying this route as I don't have a pressure bleeder and can't get one this time of year ... Jump to 5 min for the cool part - I think this is the 'reverse' bleed?

HiWind

so I'm looking into this tomorrow ....
1. bleed brakes and clutch - per Adrian's book I need a power bleeder for the clutch so I'll hopefully find one tomorrow or make one ... time of year is just wrong for the big auto spares places - all closed for the week
looks like a reasonable way to go if I can't find a motiv etc..
2. check the flexible rubber hose attached to the clutch slave cylinder for bulging - likely replace anyway
3. check for leaks although I'm not losing any brake fluid as far as I can see

Vandit

HiWind: I used a Motiv power bleeder when I bled my clutch/slave and brakes. The slave was still pretty tricky since the fluid pick-up is high on the reservoir and it's easy to get air in system. It took me several attempts before I got a clutch pedal.

I have heard of the reverse method described in that video, and while i've never tried it myself (yet!), I do not see why it wouldn't work on our cars. Give it a shot and let us know.

HiWind

thanks V - will do - wish me luck!

this excellent post from Babalouie illustrates why its likely better I just try make the bleeder if I can't borrow one tomorrow.
While doing a reverse bleed he dropped his clutch slave cylinder down to get it lower
... which was a clever technique re the reverse bleed ... but the power bleeder still found bubbles!

https://rennlist.com/forums/8775204-post8.html