Clutch pedal travel excessive Options

[peteinjp]

Not wanting to put any undue pressure on the TOB I pulled the cable end as far forward as i could while pushing the clutch lever as far back and adjusted the cable with no free play. Tube is good, cable, pressure plate, flywheel etc all have about 30,000kms. Pedal stop is low and yet I have to push the pedal all the way to the floor to keep from grinding in 1st and reverse. I can not pull the pedal back at all as described in the factory manual. It works but barely- the travel is too far even with the cable adjusted with slight pressure on the shift fork lever.

It seems to me there should always be just the slightest play in the cable- no??


Any thoughts?

Pete

[DRPHIL914]

Not wanting to put any undue pressure on the TOB I pulled the cable end as far forward as i could while pushing the clutch lever as far back and adjusted the cable with no free play. Tube is good, cable, pressure plate, flywheel etc all have about 30,000kms. Pedal stop is low and yet I have to push the pedal all the way to the floor to keep from grinding in 1st and reverse. I can not pull the pedal back at all as described in the factory manual. It works but barely- the travel is too far even with the cable adjusted with slight pressure on the shift fork lever.

It seems to me there should always be just the slightest play in the cable- no??


Any thoughts?

Pete

@peteinjp

if its grinding its not tight enough. there really should be no play at all its going to be tight and you should be feeling the car start to move when you release the pedal from the floor board about 1/4 of the way , or a bit less. if its too loose then when you press the pedal to t he floor the throw out bearing is not getting enough pressure on the presure plate to disengage the disc so its still grabbing the flywheel. I had this happen to me after installation of a new cable and clutch and i was sitting in traffic and i had the same issue. had to get under the car after it cooled and tighten the cable at the shift fork. but if its adjusted right it will not grind and it will be easy to get into gear when sitting and idling too.

PHil

[JamesM]

Not wanting to put any undue pressure on the TOB I pulled the cable end as far forward as i could while pushing the clutch lever as far back and adjusted the cable with no free play. Tube is good, cable, pressure plate, flywheel etc all have about 30,000kms. Pedal stop is low and yet I have to push the pedal all the way to the floor to keep from grinding in 1st and reverse. I can not pull the pedal back at all as described in the factory manual. It works but barely- the travel is too far even with the cable adjusted with slight pressure on the shift fork lever.

It seems to me there should always be just the slightest play in the cable- no??


Any thoughts?

Pete

Most flywheels have been machined at this point and it throws off the geometry of the clutch fork/cable setup. The fix is to install additional shims (washers) behind the clutch fork pivot ball on the trans (though this involves pulling the trans) or replace the flywheel (and still possibly re-shim the pivot fork)

If you look at the clutch fork with the cable removed you will notice there is a gap on the forward side of the clutch fork between it and the trans housing, the larger this gap when installed in the car the worse this problem is. I cant remember the factory spec but I like to shim the pivot so this gap is as small as possible without touching. Anything over 1/4" and the clutch just feels like crap to me. When setup properly you can feel the clutch go "over center" about 1/3 of the way down in the pedal travel. Most 914s I have driven you can never feel it but its a night and day difference when setup properly.

[rhodyguy]

Only 1/R? No problem up and down shifting 2 through 5?

[peteinjp]

Thanks guys-

Tube in tunnel is clean:



I can definitely tighten the cable more- that’s not a problem. The issue is that in doing so there is no free play between the cable and the release lever thus putting pressure on the TOB (and ultimately thrust surfaces in the engine?) If I adjust it to the point where the clutch release is 1/3 of the way from the floor I’d have significant pressure on the TOB but probably not enough to cause the clutch to slip.


Shifting is ok when moving- just having a hard time with 1 and R at a standstill- especially R. I had this issue once before and tightened up the cable= problem gone.

Pivot- I can not find any info in the factory manuals (engine flywheel or transaxle) about shimming specs. That said with the clutch fully depressed it seems I man getting close to hitting the the bell housing:




and with the lever just touching the TOB I have lots of room so it does seem like shimming would be a good idea to prevent interference issues as the clutch wears. I have to tear the car down in the next year or so anyway so I'll take care of that then. Any more info on the said shims would be very helpful.



That all said- it still does not seem like that would lessen the required throw. Am I over thinking the "pressure on the TOB thing?" Maybe my car just needs full travel to completely engage and release? The way it is not I can not get the free play at the pedal described in the factory lit.

BTW I have ordered the rennline clevis but will stack some washers in for the time being to get a bit more adjustment.


Thank again-

Pete

[JamesM]

That all said- it still does not seem like that would lessen the required throw. Am I over thinking the "pressure on the TOB thing?" Maybe my car just needs full travel to completely engage and release? The way it is not I can not get the free play at the pedal described in the factory lit.

Yeah thats a huge gap there with the clutch fork. 'Something' with the clutch/linkage needs to be addressed. Could need more than just shimming the pivot, I would get in there and inspect everything (pressure plate, flywheel, etc) and replace all the bushings while you are at it. I suspect possibly a worn pressure plate + disc and/or collapsed pivot bushing as well.

Shimming the pivot ball on the trans will probably have more impact on the clutch fork position than you might expect though. Given the geometry of the clutch fork with the pivot being very near the TB end, moving it a couple mm closer to the pressure plate can result in the cable end moving 1/2" or more forward.


Pulling the trans with the motor in the car isnt to big a deal if you have the necessary tools. I have done it more than a few times.

[r_towle]

I seem to recall a few “try this”

1) put a 3/4 inch long bushing on the cable end so you can adjust it more.
There was a time that some cables were too long.
Have someone push the clutch in all the way, if the pivot fork hits the case, you have adjusted it all the way.

2) bend the shift fork
3) add a spacer (stared above)
4) get a new pressure plate and possibly a new flywheel to get back into tolerance

[peteinjp]

I ordered a different clevis but for now I put in a few washers as a spacer. I considered bending the lever.... but thought I might break it with it in the car. I'll check to see if its not already bent when I pull the engine. The flywheel etc are all replaced with new items 30,000kms ago.

For now I have adjusted the first nut as tight as I can with my fingers. The clutch picks up about 1.5" from the floor stop and no grinding. There is no play in the pedal as there should be but its not so tight that I'm worried about it. Still doesn't seem quite right having the cable tight but I'll give it a go this afternoon and see how it feels.

Pete

[DRPHIL914]

I ordered a different clevis but for now I put in a few washers as a spacer. I considered bending the lever.... but thought I might break it with it in the car. I'll check to see if its not already bent when I pull the engine. The flywheel etc are all replaced with new items 30,000kms ago.

For now I have adjusted the first nut as tight as I can with my fingers. The clutch picks up about 1.5" from the floor stop and no grinding. There is no play in the pedal as there should be but its not so tight that I'm worried about it. Still doesn't seem quite right having the cable tight but I'll give it a go this afternoon and see how it feels.

Pete

sounds like its close, but as already suggested, you may still need to eventually get a new flywheel and disc, also looks like some fluid seeping so either a output shaft leak on trans or RMS leak, probably can tell which it is by the smell . right now it sounds like its driveable unless you get slipping or shuttering then its time to pull the trans and do some maintenence. EDIT- sorry i reread your post and realized your clutch and flywheel already replaced. - if there is fluid leak that will eventually make its way onto the surface and cause issues. - Phil

[brubou]

Has that tunnel been restored?! it's so clean

[930cabman]

It sure looks like a clean machine. I have not seen a mention of the free play at the pedal? I generally shoot for 1/2" or so.

[jfort]

I agree with the free play and the bushing. Mine with a bushing and adequate free play had 14mm of thread extending past the nuts

[peteinjp]

EDIT- sorry i reread your post and realized your clutch and flywheel already replaced. - if there is fluid leak that will eventually make its way onto the surface and cause issues. - Phil

Yes- the output is leaking- keeping my magnesium stuff from corroding-haha! I'll be taking care of that soon enough but for now its not so bad.

Has that tunnel been restored?! it's so clean

Yes- the whole car has been restored by Cary at Middle Motors- R.I.P. He did a fantastic job as you can see here:

Snoopy

Unfortunately the shipping company screwed me and left the car on a dock in Tacoma though a full winter so there have been pervasive corrosion issues. As the cars new custodian I feel a responsibility to both bring it back up to the condition is was in when I bought it from @raynekat. I'll start a thread but at for the last year I've been back and forth with the insurance company so I'm waiting until that's settled.

It sure looks like a clean machine. I have not seen a mention of the free play at the pedal? I generally shoot for 1/2" or so.

I have 0 travel at the pedal. The cable is under the slightest tension- if I get 1/2 of travel its very close to grinding at a standstill going into reverse. Thats why I'm scratching my head about why so much travel is required.

I agree with the free play and the bushing. Mine with a bushing and adequate free play had 14mm of thread extending past the nuts

I ordered this which may be a bit long but is a very nice looking part. I also like that it is aluminum so less likely to wear the V in lever any further.




So- would it be totally impossible to replace #5 bushing in situ?? Probably best to wait but my thought was to 3d print a thicker one in ASA.



The only other unknown that could affect the throw that I can think of is the pressure plate. It seems possible that it might have a slightly different geometry. I don't know the maker but it is listed as an aluminum unit on the Rothsport build sheet.

[Mikey914]

Shouldn't need to add in much if the flywheel hasn't been machined down too far. You will run out of throw before it disengages if it needs to be shimmed. However, DO make sure your transmission ground strap is fully grounded.
If not the cable will conduct the voltage and heat the wire. Stretching it slowly until you get exactly what you are showing. Eventually, if you keep adjusting it will snap.

It could be an alternate problem, that is very easy to fix.

[technicalninja]

Might be a tight pilot bearing if it ONLY grinds gears when stopped.

I'd determine where the clutch is starting to grab when the pedal is released.

If it's just off the floor then it will be geometry related, flywheel thickness, clutch adjustment, worn clutch disc/plate, broken/bent fork, toasted fork pivot.

If engagement is normal, then it will be something else. Tight pilot bearing, trans/engine misalignment, something else weird...

[rhodyguy]

A winter stuck in Tacoma? Outdoors? Uncovered? Right on Puget Sound, with the brisk salty air, is part of the recipe for problems. Did you rinse every section of the exterior? I would have.

[JamesM]

A lot of people seemed to be focused on cable threading. While a spacer might help a little all cables are different so the amount of threads/spacers being used are somewhat irrelevant.

One look at the picture of where the clutch fork sits with no cable installed says it all... trans needs to come out to address this properly.

Doesn't matter how you adjust the cable, install spacers on it, or bend the clutch fork, the total range of motion of the clutch fork/throw out bearing is currently limited by its position in the housing.

[930cabman]

It's possible the synchro's at 1 and reverse are shot

[Dr Evil]

The "shim" under the pivot ball is nothing more than a simple 8mm washer. No special thickness or calculations.

Consider this; you shim the pivot ball and it moves the clutch fork and TOB closer to the pressure plate. This allows you to have more travel when the clutch is pulled. Your clutch fork in the pic, if I am understanding that is in neutral position, has some potentially limited motion. When you put the second washer under the pivot ball, put teflon tape on the threads or it will slowly leak.

For the bushing in the fork, that needs changed before you drive if it is truly compromised. You will wreck parts inside of your transmission. Not worth it for less than $5 in parts, and an afternoon of work.

Click in my sig for the free 31 paged of notes and look at the clutch adjustment section. I do feel you are over thinking this. Your clutch is not releasing, your dragging it when you shift, you are damaging your rings/sliders/teeth doing this so at least adjust and see what that brings you. A proper adjustment may show you that you DO NOT need mess with the fork at all.

[rgalla9146]

I agree about the TOB pivot bushing.
After that the most likely cause is an incorrectly machined flywheel.
The position of that arm is not normal.
Full release of the disc should start with the arm much further forward toward the
engine. With good parts no shims would be needed
Another possibility is the pilot bearing, if it is tight or dragging the input shaft it can
cause your symptoms.
And one more......the throwout bearing could be very sticky on its guide tube
First step....remove trans.