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'80 931 in storage for 17 years - Clutch pedal on floor

 
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Gatornapper  



Joined: 23 Oct 2021
Posts: 294
Location: VA

PostPosted: Sat Oct 30, 2021 12:57 pm    Post subject: '80 931 in storage for 17 years - Clutch pedal on floor Reply with quote

Hope to pick up a really sweet '80 931 that has been well-stored for 17 years (weatherproof building under car cover). 58k original miles.

The clutch pedal is on the floor. I am an old mechanic with a full shop.

Of course I'll fill reservoir with fresh fluid and pump the pedal and see what happens, look for leaks. But if I find none -

Simple question: In everyone's experience here, is this more likely to be the Master cylinder? or the slave cylinder?

Just want to save some time on which one I rebuild first. I know - I should just rebuild both.......

TIA for the help.

GN
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jazz guy  



Joined: 26 Nov 2002
Posts: 434
Location: Colorado

PostPosted: Tue Nov 02, 2021 5:57 am    Post subject: Reply with quote

Common issue and the culprit is most likely the slave. Happened on two of mine. Both times the slave cylinder needed a rebuild or replacement.
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chuck21401  



Joined: 20 Feb 2005
Posts: 525
Location: Annapolis, MD

PostPosted: Thu Nov 11, 2021 2:23 am    Post subject: Re: '80 931 in storage for 17 years - Clutch pedal on floor Reply with quote

Gatornapper wrote:
Hope to pick up a really sweet '80 931 that has been well-stored for 17 years (weatherproof building under car cover). 58k original miles.

The clutch pedal is on the floor. I am an old mechanic with a full shop.

Of course I'll fill reservoir with fresh fluid and pump the pedal and see what happens, look for leaks. But if I find none -

Simple question: In everyone's experience here, is this more likely to be the Master cylinder? or the slave cylinder?

Just want to save some time on which one I rebuild first. I know - I should just rebuild both.......

TIA for the help.

GN


In my case I needed to replace both, plus the hydraulic hose.
A number of vendors offer the parts as a kit.

I also replaced the braided line from the reservoir to the master cylinder.
More details and pics here:

https://www.924board.org/viewtopic.php?t=44402&highlight=master+cylinder

I found the best part of the job to be disconnecting the MC from the clutch pedal arm. It takes some effort to get up under the dash to reach everything.

Good luck. Any pics of your 931? Low mile original cars are rare birds these days.

Edit: Nevermind....I saw the picture of you car on the other thread. Very nice...enjoy.
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Gatornapper  



Joined: 23 Oct 2021
Posts: 294
Location: VA

PostPosted: Sat Nov 13, 2021 2:09 am    Post subject: Re: '80 931 in storage for 17 years - Clutch pedal on floor Reply with quote

Thanks Chuck.

Master cylinder totally shot - never seen one so bad. piston rod totally loose.

I am small so squeezing under to disconnect rod is difficult, but I can do it.

My bigger concern is how to get to master cylinder......seems almost inaccessible unless I remove brake master cylinder and booster.

Hoping slave is ok, but will replace lines as well and find out.

Car has 58k miles, proven. So maybe slave is ok.

Surprised master cylinder went out so early.

GN

chuck21401 wrote:
Gatornapper wrote:
Hope to pick up a really sweet '80 931 that has been well-stored for 17 years (weatherproof building under car cover). 58k original miles.

The clutch pedal is on the floor. I am an old mechanic with a full shop.

Of course I'll fill reservoir with fresh fluid and pump the pedal and see what happens, look for leaks. But if I find none -

Simple question: In everyone's experience here, is this more likely to be the Master cylinder? or the slave cylinder?

Just want to save some time on which one I rebuild first. I know - I should just rebuild both.......

TIA for the help.

GN


In my case I needed to replace both, plus the hydraulic hose.
A number of vendors offer the parts as a kit.

I also replaced the braided line from the reservoir to the master cylinder.
More details and pics here:

https://www.924board.org/viewtopic.php?t=44402&highlight=master+cylinder

I found the best part of the job to be disconnecting the MC from the clutch pedal arm. It takes some effort to get up under the dash to reach everything.

Good luck. Any pics of your 931? Low mile original cars are rare birds these days.

Edit: Nevermind....I saw the picture of you car on the other thread. Very nice...enjoy.
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chuck21401  



Joined: 20 Feb 2005
Posts: 525
Location: Annapolis, MD

PostPosted: Sat Nov 13, 2021 11:22 pm    Post subject: Re: '80 931 in storage for 17 years - Clutch pedal on floor Reply with quote

Gatornapper wrote:

Car has 58k miles, proven. So maybe slave is ok.

Surprised master cylinder went out so early.


With my car both the master and slave were replaced in recent history but both needed to be replaced again. From what I understand, it's not the mileage so much as moist air entering the reservoir system and then being absorbed into the hydraulic fluid. Some discussion on this thread: https://www.924board.org/viewtopic.php?t=34855&sid=00e00329bac141c05b673bfa0499915e
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Gatornapper  



Joined: 23 Oct 2021
Posts: 294
Location: VA

PostPosted: Sun Nov 14, 2021 11:28 am    Post subject: Re: '80 931 in storage for 17 years - Clutch pedal on floor Reply with quote

Watched videos today on replacing both master & slave - pretty cut & dried. Master very difficult to reach, but possible obviously. Slave much easier once starter is removed.

So to have a good baseline on the car, I'm replacing both. Will closely inspect the line and replace it too if it looks weak.

GN


chuck21401 wrote:
Gatornapper wrote:

Car has 58k miles, proven. So maybe slave is ok.

Surprised master cylinder went out so early.


With my car both the master and slave were replaced in recent history but both needed to be replaced again. From what I understand, it's not the mileage so much as moist air entering the reservoir system and then being absorbed into the hydraulic fluid. Some discussion on this thread: https://www.924board.org/viewtopic.php?t=34855&sid=00e00329bac141c05b673bfa0499915e
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Gatornapper  



Joined: 23 Oct 2021
Posts: 294
Location: VA

PostPosted: Sun Dec 05, 2021 12:22 am    Post subject: Reply with quote

Clutch master cylinder OUT, picking up new one today.

Slave cylinder on way from Pelican and will be here Thursday.

GN
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iambhooper  



Joined: 30 Dec 2021
Posts: 13
Location: Greensboro NC

PostPosted: Mon Jan 03, 2022 12:27 pm    Post subject: Reply with quote

Gatornapper wrote:
Clutch master cylinder OUT, picking up new one today.

Slave cylinder on way from Pelican and will be here Thursday.

GN


Did that fix the problem?
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87 924s (1st Porsche) project
1986 Fiero Gt
1990 DA Integra STL
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MikeDanger  



Joined: 21 Nov 2002
Posts: 770
Location: Denver

PostPosted: Mon Jan 03, 2022 5:09 pm    Post subject: Reply with quote

You should check the Brake MC for leaks, your Booster could be full of fluid, Also check the Firewall for cracks at the Clutch MC, before your firewall blows out!
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