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Clutching, but no straws - Gearchange/Gearbox/Clutch - The Lotus Forums Jump to content


Clutching, but no straws


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Finally finished Andjohns' (Andy's) S4, and engine is running sweeeeet. However, we are presented with yet another conundrum...

Box has been away to replace 2nd gear, synchro and hub, flywheel skimmed, new clutch assembly and slave cylinder. Everything measured and within tolerances, no air in the system. Clutch bite is around halfway on the pedal, and forward gears are pretty good. BUT, any attempt to engage reverse causes severe grinding. Clearly stuff is spinning and fast! Took box and clutch off again last night and checked everything was fine, put it back together, and same problem.

I've checked our stock and we're right out of epiphanies. Anyone got any great ideas?

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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Double check adjustments for gearchange. Can you manually move the cross shaft to select every gear with translator disconnected?

Edited by DanR

DanR

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Cheers Danny. Nothing to do with translator or adjustment. In fact, yesterday's test was with engine running and selecting gears by hand on the cross shaft. All forward gear selections fine, but reverse crunches badly.

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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If clutch is biting and forward gears are selecting it cannot have anything to do with flywheel, clutch or slave cylinder. If you have eliminated any gear linkage problems I can only think of some problem in gearbox. Might the repair to 2nd gear and synchro have have caused some other problem in the box.

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Is it possible that the pilot bushing is binding up on the input shaft causing the box to receive power even with the clutch disengaged? I know you stated everything is "fine" with regards to clutch, but unless the clutch plate is dragging, the only other part of the input shaft that that is connected besides the splines would be the very tip of the input shaft which resides in the end of the crankshaft. What happens if you try to start the engine with the box already in reverse? Do you get a rough disengagement from the box when going back into neutral?

Just a few thoughts that come to mind.

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Can you put in reverse with engine off, then try starting with clutch depressed. I'm not sure what that proves, but might tell you if it's clutch drag, but I don't see how it can be because the clutch doesn't know which gear it is.

Reverse doesn't have syncro does it.

Confused

Roger

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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Only the last boxes had a syncro on reverse I think. There is a brake on the reverse cog. Maybe that's playing up. Also there could be a problem with the shift rod locks.

Can you get reverse after shifting into first. Doing that should stop the mainshaft spinning from inertia.

Otherwise fear the only way to find reverse will be on the workbench.

DanR

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This may be a long shot, but as the box has been stripped, is it possible that the reverse gear has been put on back to front, thus not allowing it to mesh ?

Caught between a rock and a hard place in a catch 22 situation, So its 6 of one and half a dozen of the other. Your damned if you do, but your damned if you don't so shut your cock!!!!!!!!!!!

Lotus Espirt Turbo S3    

Lotus Esprit S4 

Lotus Elise S2 Sport 130

pig_zps6d7342f1.jpg

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Cheers chaps. Responding to various above: the spigot bearing is OK, and the input shaft engages fine. Everything points to clutch drag but I've never had a new clutch do this before. Have tried all the startup in/out of gear options and all feels good except engaging reverse which, as Roger states, has no synchro. Engaging first then reverse doesn't help at all. Reverse CAN be engaged, but only if forced and with lots of noise, so we won't be doing that again! I think all we can do is throw the old clutch in as a control test...

Edited by sparky

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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Try adjusting the slave rod to the point where you can confirm there's no clutch drag? Don't overdo it as the diaphram doesn't like being over extended. If you can get reverse easily then you'll need to check the clutch set-up.

DanR

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Danny - thanks. Have already overextended the release arm adjustment by 5mm but to no effect. Will try and push that a little higher.

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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My money is still on some problem with the gearbox cogs. As its been stripped its likely not to have been reassembled properly. Take it back to whovever did the work.

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"Hang on lads, I've got an idea".

Jack the back up (secure it well) and start with reverse already engaged, let it run a few minutes and then gradually apply some drag, hand or foot brake, gradually increase drag and rpm so as not to stall.

I'm not sure what's happening here but it may just free something up. It doesn't sound like clutch which only leaves something not as free as it should be.

Roger

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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Sparky,

I had the same problem on an SE clutch I replaced for a friend recently. The gearbox was fine before the clutch but grinding reverse after and the box was never touched other than removing it.

We tried everything including bleeding numerous times, replacing the master cylinder and nothing worked. We finally fabricated a slightly longer slave/fork pushrod and that solved the problem. I still don't know what caused it but my suspicion is something slightly different about the new clutch.

I also had some communication with someone else around the same time with the same issue. I'll try to contact him and see what he worked out.

Have you checked the pushrod/fork travel to see if it's correct?

1995 S4s

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Thanks for all your input chaps - issue resolved! Well, will be tomorrow.

Let's have a laff - first one to guess the problem wins a free exhaust bracket field dressing. I know Pilko will be gagging for this one.

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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Ouch! You have offended me, sir. Lagers at dawn!

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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System not bled?

Caught between a rock and a hard place in a catch 22 situation, So its 6 of one and half a dozen of the other. Your damned if you do, but your damned if you don't so shut your cock!!!!!!!!!!!

Lotus Espirt Turbo S3    

Lotus Esprit S4 

Lotus Elise S2 Sport 130

pig_zps6d7342f1.jpg

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Tut tut Graham, looks like the matching set of cable ties will go to another lucky contestant.

System not bled? Tish pshaw.

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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