Hi last couple of days my MK1 1.6 has been having a gearbox issue.
Randomly it wont let me select a gear, sometimes fully declutching allows me to select gears again. Then other time it takes a good few attempts.
It is not affected by being warm or cold or by any particular gear.
Whats first to check?
Cheers
James
G’day James
Sounds like a problem with the clutch slave cylinder. There is info in the tech FAQ http://www.mx5oc.co.uk/forum/forums/t/827.aspx
Agreed
Brilliant link, chers guys! Will get right on it, £15 for part, bargain, loving MX5 ownership!
Hi James, yes a good link, but do use rubber grease or silicone grease for the end of the pushrod inside the rubber boot. Engine oil (mineral) on the boot and seal is often the reason for clutch slaves failing.
Rubber grease (usually red) is based on castor oil rather than mineral oil and will not swell and damage the rubber seals. Easiest source these days is probably eBay,
Likewise silicone grease will do fine outside the fluid system (not for seal rebuilds) and is probably more useful to have around,
Guys, spent Sat chaging over to a new slave cylinder, and bled it with my pressurised kit, but am stil having problems. Bled it again today to make sure, got good pedal pressur eand feel, but if the clutch is depressed fully its sometimes sticking, meaning I can’t select a gear.
Checked for leaks, noe to see at the Master Cylinder, and none along the pipes. Checked the bleed nipple and the flared pipe , all ok no leaks, checked the pushrod and going in and out fine.
Any suggestion before I stick it in the garage? PS I also flushed it out completely the second time to make sure all the fluid was brand new.
Cheers
I’ve known the spigiot bearing to work its way out of the flywheel before and cause the input shaft to drag. It’s a box out job to check though.
Yes or sticking clutch plate splines. Robbie might know if you can get to them perhaps through the release arm hole to give them a squirt of brake cleaner without dismantling.
Try first to determine if it’s a gbox or clutch fault. Press the clutch down fully, slowly, in neutral and listen carefully to see if the noise changes. This is often more noticable when hot, in a quiet garage with the hood up; if the clutch is releasing you’ll hear the rattle of the gbox input shaft going round stop as the clutch releases. Try then to select 1st. If that won’t go try 2nd etc. If you can hear the clutch releasing the main shaft and the gear won’t select it’s likely to be a gbox selector issue. Also worth checking for correct level and grade of gear oil.
This might also be worth exploring, from the thread next to yours, gearbox shift lever boot package, http://www.mx5parts.co.uk/product_info.php/products_id/1111
Don’t know if this helps diagnose it further, but I drove it yesterday and it was fine. Drove it this morning, fine but a little notchy. But I did notice when in first gear with the clutch fullly drepressed , it was trying to creep forward?
Cheers
Just saw your link , yes the transmission tunnel does get hot and the gear change is notchy… might be worth chaging for £40 odd quid just to remove that from suspect components list.
There should be no creep forward til you raise the clutch from the floor.
Make sure the pedal can go down fully and that it’s not being stopped by mats or carpets. Get someone to press the clutch while you see if the slave pushrod is actually moving. Check the linkage isn’t worn.
Idle the engine, press clutch hard to floor, wait a few seconds for plate to stop spinning and try to engage reverse. Keep clutch fully down and try first, then switch between the 2 gears. Let the clutch lever up a fraction, 1/2" or so, and try again. It will not let you select at the point the clutch is starting to bite.
If it is definitely dragging you’re back to re-bleeding and checking for linkage wear. If ok then it may be the plate sticking for several reasons, sticky splines, spigot bush, or even the clutch cover not lifting evenly so eliminate the easy stuff first.
All this said, I had an MGB that was a pig to bleed and was behaving like yours. The slave lies horizontally and below the master and it can be hard to get all the air out. You can end up with air going up and down the line. Have plenty of fluid on hand and work the air through in a series of long pedal strokes whilst refilling the master and without a break so the air is expelled at the bottom slave before it has chance to rise back up through the line. Tap the slave gently with a soft hammer to dislodge bubbles and close the nipple just before the end of a full downstroke. After a few days mine cleared itself fully so I think the remaining air eventually worked itself out. A bubble may have found its way up the line and out through the master. Persevere and good luck.
Many thanks to everyone for the feedback.
After a few months of driving around the problem and knocking it out of gear when stopping at light etc, and after a couple more attempts at bleeding I stuck her in the garage down the road.
Who promptly diagnosed a faulty master cylinder! They said I would not have been able to see it from the engine bay as its at the other end in the foot well by the lever.
So ordered a new one up to fit myself (not paying £45 a hour labour!!) so any pointers on fitting a MX5 clutch master cylinder much appreciated!!
Still loving the little devil!
Got another issue not, every now and then she bogs down under hard acceleration, (then clears and pull away nicely) any ideas?
Well done, makes sense.probably losing some of the movement in the first part of the pedal travel.
Not fitted one, others will know I’m sure.
The driving issue would say plugs and points to me but you haven’t any points so do the plugs and plug leads if they haven’t been done for a while 