clutch return spring

[made in berlin]

89 944 is the clutch return spring a difficult repair?

[9FF]

There is no clutch return spring, there is a release bearing and an actuating arm. There is a cantilever spring on the clutch pedal but that usually isn't the problem. If your clutch pedal won't return it normally means you have a hydraulic leak so you need to fix the leak and bleed the system. Normally the leaks emanate internally from the master or slave cylinders or the pipe that joins them. WYIT replace all three is the general consensus.

[v2rocket_aka944]

There is a return spring and a power spring on the pedal. Replacing either isn't that difficult. I run without either presently and the car drives fine.

[9FF]

Originally Posted by v2rocket_aka944

There is a return spring and a power spring on the pedal. Replacing either isn't that difficult. I run without either presently and the car drives fine.

That is not a return spring on the pedal, it works like a cantilever, when the pedal reaches a certain point it brings it back. If it was a return spring for the pedal then without hydraulics when you pressed the clutch in, it would come back by itself. However that doesn't happen, the pedal stays on the floor.

[v2rocket_aka944]

Even in the OEM diagram there is a return spring listed and illustrated, above the power spring on the pedal

See on pelican catalog...321 721 191-oem

[9FF]

Originally Posted by v2rocket_aka944

Even in the OEM diagram there is a return spring listed and illustrated, above the power spring on the pedal

See on pelican catalog...321 721 191-oem

Yet it doesn't return the clutch pedal when it's on the floor, it needs hydraulic back-pressure to work. When your clutch hydraulics are not bled properly or leaking that pedal will stay on the floor and you'll be lifting it up with your toe. That's no return spring in the traditional sense of the word.

What I'm trying to portray to the op is that if he has a problem with the clutch pedal not returning it's not that "return spring", more likely clutch hydraulics are leaking.

[MB968]

As noted above, there is no return spring that will pull the clutch from the floor. If that is your problem, this spring will have no effect.

On the 968, can't speak for 944, the spring noted returns the clutch pedal to the full up position once it is within about 1" of the top. At this point, the linkage that this spring is attached to, toggles over, and this spring pushes above the pivot point on the clutch pedal lever to push it the rest of the way up.

[made in berlin]

Thank you for the advice much appreciated! If I could ask , are the recommended clutch repairs (master cylinder, slave) a difficult repair.

[alan6272]

The clutch master and slave cylinders are not a difficult repair but that depends on the persons ability. The starter will have to be removed for the slave and bleeding them could be a pita. I suggest you read clarksgarage.com I also run with out springs on my peddle but mine is an 83.

[veleno]

Whether you're doing it by yourself or with a buddy, buy a power bleeder! It makes life easier.

Like mentioned above, replacement of all 3 items at the same time is a good idea (master, slave, hardline between the two). I would also recommend you replace the blue hose from the brake master to the clutch master at the same time.

[rbuswell]

I am in the midst of replacing the clutch master cylinder. The car is a 1987 924S and new to me. It is missing several important parts including the return spring. Contrary to an earlier post, the return spring (part #4 in the PET drawing) does appear to have a valid function; returning the clutch pedal all the way to the stop.

My question is: where does the spring attach under the dash? There is supposed to be a hole in the lever/arm which I'm still looking for but no indication in the PET, shop manual or elsewhere where the other end of the spring loops to provide the pull to bring the pedal back to its stop.

[9FF]

Originally Posted by rbuswell

I am in the midst of replacing the clutch master cylinder. The car is a 1987 924S and new to me. It is missing several important parts including the return spring. Contrary to an earlier post, the return spring (part #4 in the PET drawing) does appear to have a valid function; returning the clutch pedal all the way to the stop.

My question is: where does the spring attach under the dash? There is supposed to be a hole in the lever/arm which I'm still looking for but no indication in the PET, shop manual or elsewhere where the other end of the spring loops to provide the pull to bring the pedal back to its stop.

As per the earlier post there is no actual “return” spring, there is nothing attached to the clutch pedal that exerts spring pressure when you press the pedal down or to return it when you release it. There is instead a spring in the clutch mechanism but the system works by cantilever action, so when the clutch reaches a set point, about half travel back to rest, the cantilever will engage and pull it all the way home. One thing to be aware of is if you have any air in the clutch hydraulics then you will loose any cantilever action provided by that spring and your clutch pedal will sit at the bottom. So you need to fix any leaks for the clutch pedal to operate and have any chance of returning to its home (clutch out) position.

[rbuswell]

Unfortunately, I have never been able to get the Pelican Parts forums to use my uploaded photos in my posts. If you look at page 140 of the E_924S_88_KATALOG.pdf available from the PCNA website, the return spring (part # 4) is clearly there and I was able to order one from a dealer. When I looked at the actual pedal more closely, my car has a totally different design. There is no extension of the lever arm above where the bolt (part # 8) goes through for both the brake and clutch pedal levers. The same vintage 944 PET shows the clutch lever as being identical. This is disconcerting in that the PET doesn't illustrate my pedal design. It is also disconcerting because the return spring in the PET appears to have a safety function in the event of clutch failure.

I do disagree with you that there is no spring or assistance action in the pedal assembly. The clutch power spring (part # 4A) definitely provides assistance or buffering action respectively to the pedal in each direction.

Nevertheless I appreciate your response as it did help me to solve the mystery. Now I have an extra return spring that most likely works on an older car.

[9FF]

Originally Posted by rbuswell

...I do disagree with you that there is no spring or assistance action in the pedal assembly. The clutch power spring (part # 4A) definitely provides assistance or buffering action respectively to the pedal in each direction...

Like I said it’s a cantilever action rather than a typical return spring. I’ll put it this way, if you drain all the hydraulic fluid from the clutch system a traditional “return spring” would still provide resistance on the downstroke and a return action on the clutch pedal. However on a 944, if you drain all the clutch hydraulic fluid the “return spring” ( PET #4A) will not provide any resistance on the downstroke of the clutch pedal or provide any return action for it, in fact the clutch pedal will remain firmly on the floor.

Many folk find this out when they have air in the clutch hydraulics, the pedal won’t return and stays on the floor however, if they use their toe to “assist” the pedal off the floor, about half way up the cantilever action of the spring will take over and bring it all the way up.

I’m not sure what the issue you are having with your clutch though, it seems strange that you have parts in there that don’t relate to PET. Likely a po hack when they had air in the system and wanted to force the pedal up maybe?

[rbuswell]

... the clutch master cylinder is not in the car so there is no hydraulic action whatsover yet the clutch power spring definitely provides assistance/resistance in both directions when you move the pedal by hand up and by hand or foot down. The return spring (part # 4) is not the same as the clutch power spring (part # 4A). The return spring is a much smaller spring exactly like the return spring on the brake pedal lever and it's a good idea that has been deleted for some reason.

I'm assuming that you didn't take a look at the PET yet. I understand what you mean by cantilevered but that isn't happening in the clutch. Your earliest post reads like there were no springs at all in the clutch pedal assembly and the only force is exerted from the hydraulics or the clutch itself. The PET shows two springs. This may be a semantics problem. To me the clutch is the system in the bell housing immediately behind the engine, not the pedal assembly. In the PET it's called a pedal cluster. That was the source of my confusion.

I'd be curious what you think of the fact that there isn't a clutch pedal lever anything like the one in my car illustrated in the PET, either 924S or 944. It all looks Porsche correct so I don't believe it is out of another car. It just never made it into the PET. Weird.

[9FF]

Originally Posted by rbuswell

... yet the clutch power spring definitely provides assistance/resistance in both directions when you move the pedal by hand up and by hand or foot down....

I’m definitely confused by how you describe your clutch operation. I’ve looked at masses of 944 clutch mechanisms and never come across one that works as you describe. I took a video below of a car in my shop right now that doesn’t have clutch hydraulics, and also a picture of the cantilever spring I’ve previously described. You will notice that there is negligible resistance to my finger pushing the pedal down until it gets to about half way (the cantilever point) when it snaps down. Once down the pedal will not return without pulling up with my finger, and again there’s no spring assistance until I pull it up about half way when the cantilever spring takes over again and pulls it up.

https://youtu.be/48cma2pk4Gc

[rbuswell]

We are clearly not getting through to each other. Here are the sentences you wrote that caused me some confusion:

"As per the earlier post there is no actual “return” spring, there is nothing attached to the clutch pedal that exerts spring pressure when you press the pedal down or to return it when you release it. There is instead a spring in the clutch mechanism but the system works by cantilever action, so when the clutch reaches a set point, about half travel back to rest, the cantilever will engage and pull it all the way home." This made me think that you were talking about a spring in the clutch assembly itself. Keep in mind that my other car is a '82 911 which does have a spring in the clutch mechanism since it is actuated by a cable, not hydraulics. This sentence didn't make any sense for a hydraulic clutch.

"Like I said it’s a cantilever action rather than a typical return spring. I’ll put it this way, if you drain all the hydraulic fluid from the clutch system a traditional “return spring” would still provide resistance on the downstroke and a return action on the clutch pedal. However on a 944, if you drain all the clutch hydraulic fluid the “return spring” ( PET #4A) will not provide any resistance on the downstroke of the clutch pedal or provide any return action for it, in fact the clutch pedal will remain firmly on the floor." If there was no spring at all, your statement that there would be no resistance would be correct. It would just freely flop back and forth regardless of the cantilever arm. The only resistance would come from the hydraulic pressure of the master cylinder if it was installed and bled correctly. But there is clearly initial resistance in your video (in both directions) created by the clutch power spring visible in your photo. The spring then provides assistance or buffer when the cantilever crossover point is reached (depending on direction). I just looked at the spring when doing what you did for your video. The spring is definitely at work in both directions.

I don't want to beat a dead horse. I appreciate your assistance very much. It has given me assurance that I am not missing something based on the PET illustration. My clutch pedal lever is not the same as the PET and there is no return spring. It is difficult to see up there and the fact that the pedal wouldn't return on it's own lead me to believe there was a missing return spring. Now that I know that my pedal assembly shouldn't have one, my mind is at ease.

[IdahoDoug]

Just a quick comment here for when you get the pedal cluster and new master cylinder installed. I put a new clutch, slave and related parts in my 84 and I'm reasonably proficient. But the adjustment on the clutch pedal for where it engages and such was a nightmare to get right. It's the threaded rod that goes through the firewall. I had clutch slippage one day, then super high clutch pedal disengagement the next. I finally threw out the factory adjustment procedure and did it by feel. So if/when you get to that point, beware it may be the finickiest clutch pedal you've ever adjusted. There's a very nice sweet spot that shows maturity of design by Porsche, but getting to it was an art.

[rbuswell]

Originally Posted by IdahoDoug

Just a quick comment here for when you get the pedal cluster and new master cylinder installed. I put a new clutch, slave and related parts in my 84 and I'm reasonably proficient. But the adjustment on the clutch pedal for where it engages and such was a nightmare to get right. It's the threaded rod that goes through the firewall. I had clutch slippage one day, then super high clutch pedal disengagement the next. I finally threw out the factory adjustment procedure and did it by feel. So if/when you get to that point, beware it may be the finickiest clutch pedal you've ever adjusted. There's a very nice sweet spot that shows maturity of design by Porsche, but getting to it was an art.

Wise counsel. The Bruce's Garage procedure emphasizes that when removing the old master cylinder to measure the length of the rod and install the old clevis as close to exactly the same length as possible. I suspect there will be lots of changing of the length after it's in place anyway. I'm not replacing the clutch BTW, so it may not be as difficult for me.

[9FF]

Originally Posted by rbuswell

...I don't want to beat a dead horse. I appreciate your assistance very much. It has given me assurance that I am not missing something based on the PET illustration. My clutch pedal lever is not the same as the PET and there is no return spring. It is difficult to see up there and the fact that the pedal wouldn't return on it's own lead me to believe there was a missing return spring. Now that I know that my pedal assembly shouldn't have one, my mind is at ease....

Lets beat this dead horse one more time as I hate to leave things at loose ends, so I did a bit more digging around and wrote up this summary that might help folk in the future: Porsche 924/944 Clutch Pedal Action Explained

Anyone, please feel free to correct me if I'm wrong.