915 Tranny issue diagnosis needed...

[agfours]

Been searching the forum but haven't found an answer in direct response to a couple questions -

Recently, when cold at first startup, I'm having trouble engaging ANY gear. I used to be able to 'pre-engage' any gear without issue (push the lever 1/2 way in to a gear until I get the firm spongey pillow resistance). Now, I get a hard wall of resistance before ANY gear unless I keep rowing through and/or blip the throttle in neutral. It doesn't grind in 1-5, just hard wall of no-go resistance plus grind in reverse.

I don't get this problem while driving. Doesn't seem to happen as often if the car is warm.

Additional data points (may or may not be related, but for full symptom analysis
1. At a stop light, from neutral, I used to be able to consistently touch 2nd before 1st and it would slide like butter right in to 1st given 8 out of 10 times. Now, touching 2nd doesn't work that often, but touching 3rd does work better. This used to be the opposite.

2. When I use 5th gear, and disengage it (at speed) to prepare for a downshift, it seems to really eject the gear lever with a riddance. No grinding, just stiff against the spring when engaging.

3. When downshifting to 4th or 3rd at speed, I need to hold the lever in 'pre-engage' position for a second or two before engaging gear to prevent either refused shift and/or a grind. No problems on upshifts.

About 2000 miles ago, I replaced the clutch cable, changed to Kendall gear lube, installed all new shift bushings, Seine kit, and Wevo Shift coupler. I have new engine / trans mounts in hand, but not installed yet.

Prior to my ownership the trans got a new 1st and 2nd gear shaft (the $2300 part) plus other rebuild parts, new clutch, TOB, etc. about 10k miiles ago (I have the itemized rebuild receipt from PO). About 69k miles on car.

Has the new clutch cable stretched or is this symptomatic of something else?

Help!!

[Oh Haha]

Hard to tell exactly but I would start with the clutch cable. Adjust to specs and see if the condition improves.

Also, check the condition of your transmission and motor mounts. If old and worn out they could be allowing movement under torque, causing misalignment of the linkage and bits.

EDIT- check the shift coupler adjustment as well. Even if it's slightly out of whack it can create problems.

[Walt Fricke]

Kind of sounds like a clutch issue.

With car parked on street with some room, engine off, put car in gear. Depress clutch. Start engine. See if the car moves or wants to move. You can do this kind of thing in your garage, but have to be careful.

That may be too easy, but it seems like you may not be getting full disengagement. I suppose your coupler could be a hair off in its rotation adjustment

[agfours]

Originally Posted by Oh Haha

Hard to tell exactly but I would start with the clutch cable. Adjust to specs and see if the condition improves.

Also, check the condition of your transmission and motor mounts. If old and worn out they could be allowing movement under torque, causing misalignment of the linkage and bits.

EDIT- check the shift coupler adjustment as well. Even if it's slightly out of whack it can create problems.

I'll definately check the cable and the mounts. All was working well after install of the cable and the wevo coupler around 2k mis. ago. This issue has crept up since then (about 2 weeks / 300 miles ago).

Originally Posted by Walt Fricke

Kind of sounds like a clutch issue.

With car parked on street with some room, engine off, put car in gear. Depress clutch. Start engine. See if the car moves or wants to move. You can do this kind of thing in your garage, but have to be careful.

That may be too easy, but it seems like you may not be getting full disengagement. I suppose your coupler could be a hair off in its rotation adjustment

Thanks Walt. Just tried this and the car did not move. interesting thing though...I usually park in 1st gear. I can move the lever out of 1st and into other gears easily prior to starting the car. Then, once I start the car (in neutral with clutch depressed), the problem starts (hard wall resistance trying to get it back into first and other gears.)

[Walt Fricke]

So the clutch engagement point - where in its travel the pedal is when the clutch starfts to do its thing - is about where it has been? If so, at least that would tend to rule out clutch adjustment.

And it doesn't seem like you have clutch drag, as in a piece of a rubber centered clutch disk being where it shouldn't be.

[agfours]

Originally Posted by Walt Fricke

So the clutch engagement point - where in its travel the pedal is when the clutch starfts to do its thing - is about where it has been? If so, at least that would tend to rule out clutch adjustment.

And it doesn't seem like you have clutch drag, as in a piece of a rubber centered clutch disk being where it shouldn't be.

The engagement point is about 1/4 of the way up on pedal travel, with full engagement about 2/3 the way up.

I haven't noticed a change in the pickup point.

[schumicat]

I would safely support the rear of car on jack stands and see if the wheels turn with the clutch pedal fully depressed and car in gear. if so your clutch is not fully disengaging.

[Peter Zimmermann]

Something is wrong with the clutch, and it might not be the cable. It's possible that the roll pin that holds the clutch pedal arm to the cross shaft in the pedal cluster is failing. Or, it's also possible that the throw out bearing release fork has cracked, just enough to change the clutch adjustment. FYI; your engagement point is too close to the floor for a properly adjusted clutch.

[agfours]

Originally Posted by schumicat

I would safely support the rear of car on jack stands and see if the wheels turn with the clutch pedal fully depressed and car in gear. if so your clutch is not fully disengaging.

Thanks, I'll confirm with that approach.

Originally Posted by Peter Zimmermann

Something is wrong with the clutch, and it might not be the cable. It's possible that the roll pin that holds the clutch pedal arm to the cross shaft in the pedal cluster is failing. Or, it's also possible that the throw out bearing release fork has cracked, just enough to change the clutch adjustment. FYI; your engagement point is too close to the floor for a properly adjusted clutch.

Thanks Peter, on that advice, I went ahead and ordered the $14 brass bushing rebuild kit that comes with the roll pin. I'm sure freshening up the pedal assembly is due in any case and it appears to be a straightforward little project. I'll double check the cable adjustment - I assume that's the only adjustment...correct?

Oddly enough, just this morning before driving out of the driveway, I moved my seat by one detent and the perceived pickup point was much lower (the 1/4 travel upward). I later moved my seat forward to its usual position, and it seemed to my foot/brain that the pickup point was more like 1/2 way up....guess I need to get more scientific in my measurement.

[Peter Zimmermann]

Originally Posted by agfours

Thanks Peter, on that advice, I went ahead and ordered the $14 brass bushing rebuild kit that comes with the roll pin. I'm sure freshening up the pedal assembly is due in any case and it appears to be a straightforward little project. I'll double check the cable adjustment - I assume that's the only adjustment...correct?

Oddly enough, just this morning before driving out of the driveway, I moved my seat by one detent and the perceived pickup point was much lower (the 1/4 travel upward). I later moved my seat forward to its usual position, and it seemed to my foot/brain that the pickup point was more like 1/2 way up....guess I need to get more scientific in my measurement.

I hope that you have a manual that describes the adjustment procedure for your car, it's a bit tricky and there's an order to the job. Cable stretch, after a new install, is very unusual, so I'm guessing that the initial set-up might have been off a bit, or the adjustment bolt has backed off somehow. Either that, or something in the linkage (usually the pin or fork) is failing. Another thought; does your clutch cable say "Made In West(ern) Germany" in white letters along its black bowden tube?

FYI; call me old-fashioned, but I don't like the brass bushings for pedal clusters. I prefer the o.e. plastic parts only because they won't wear out the expensive metal parts that they rub against, and with the plastic there is no issue about what grease to use for the longest possible life.

[agfours]

Originally Posted by Peter Zimmermann

I hope that you have a manual that describes the adjustment procedure for your car, it's a bit tricky and there's an order to the job. Cable stretch, after a new install, is very unusual, so I'm guessing that the initial set-up might have been off a bit, or the adjustment bolt has backed off somehow. Either that, or something in the linkage (usually the pin or fork) is failing. Another thought; does your clutch cable say "Made In West(ern) Germany" in white letters along its black bowden tube?

FYI; call me old-fashioned, but I don't like the brass bushings for pedal clusters. I prefer the o.e. plastic parts only because they won't wear out the expensive metal parts that they rub against, and with the plastic there is no issue about what grease to use for the longest possible life.

Yes, I used the Bentley manual as well as the 101 projects for reference, and took my time step by step when I adjusted the cable upon install. It has been working great until the last 300 miles or so, so I'll check the nut to make sure it's still within adjustment tolerance. IIRC there were two adjustments: a smaller gap, in which I used feeler gauges, and a 25mm (IIRC) gap on the larger adjustment (and I'd give myself +/- 0.5mm accuracy on the larger adjustment). I'll have to check the cable for that veribiage on the cable - it was the one here on Pelican for ~$70 - I believe the brand was Gemo.

RE: the comment on the type of grease to use, is there any issue using the typical lithium or teflon based grease on the brass fittings in your experience?

[Peter Zimmermann]

Originally Posted by agfours

Yes, I used the Bentley manual as well as the 101 projects for reference, and took my time step by step when I adjusted the cable upon install. It has been working great until the last 300 miles or so, so I'll check the nut to make sure it's still within adjustment tolerance. IIRC there were two adjustments: a smaller gap, in which I used feeler gauges, and a 25mm (IIRC) gap on the larger adjustment (and I'd give myself +/- 0.5mm accuracy on the larger adjustment). I'll have to check the cable for that veribiage on the cable - it was the one here on Pelican for ~$70 - I believe the brand was Gemo.

RE: the comment on the type of grease to use, is there any issue using the typical lithium or teflon based grease on the brass fittings in your experience?

Grease for metal bushings; I like a lithium based grease, but take that with a grain of salt because the only car I've ever used the metal bushings on was my E/P race car. The pedals were easy to remove, clean, and install, so I have no long-life success stories for you. That said, my shop removed a lot of pedal assemblies with metal bushings, replaced a lot of worn shafts (we actually kept clutch pedal shafts for different models in stock), installed new o.e. bushings, and sent the cars on their way.

If your CC says Made In West Germany on it I will advise you to remove it ASAP and discard it. That cable will be an aftermarket version of the o.e. cable, and I've personally corrected many clutch linkage issues by replacing those cables (installed by others). I'm pretty sure our host has factory cables in stock, if not get one from your closest P-car dealer.

[agfours]

I just wanted to post a follow up (have for some time, but finally getting around to it!).

I got under the car and checked the clutch cable, which to my suprise, was loose enought to where I could pull it off of the arm. I scratched my head a couple of times, as I swore I was very cautious when I had meticulously followed Bentley and 101 projects process to adjust initially. So, I decided to investigate further....

What I found was that the clutch pedal was not returning to the full upright position by about 1/4". I tied a string around the clutch pedal so that I could get under the car and see that the clutch cable was not properly adjusted once I pulled the pedal to full upright position (even with the brake pedal).

So, I propped the clutch pedal in the full upright position with a large 22mm open end wrench against the firewall, and re-adjusted the clutch cable to specs. Seems that has corrected the issue.

I did not end up rebuilding the pedal assembly, as it seemed tight, with no play in the bushings. Seems that the during the original adjustment, the clutch pedal was simply not returning to the full upright position, due to the return/helper spring reducing any slack, holding it in a slightly depressed plane...

I'm not sure if the need to prop the pedal in the full upright position is just not well enough covered, is part of tribal knowledge, or if is an indicator of something else I'm overlooking, but hopefully this pays forward what I found in the process and can generate any further clarifications.

Thanks to all for the spot-on advice!!