13 replies to this topic

[PravSridhar]

Hi folks,

 

This is my first post on this forum!

 

I drive a 1987 Mini Mayfair (a.k.a "Winston"). A few months ago the clutch slave cylinder packed up (fluid was leaking badly) and the clutch pedal dropped to the floor. I have had the slave cylinder replaced and the clutch works fine and so do the gears.

 

While the gears (all 5) slot perfectly on a cold start and for the first say 5 miles... the gears start to get notchy, especially 1st. And when this starts to happen, the reverse gear crunches quite badly! However, when this happens, the clutch still has the same action as it always did and there is normal pressure/action in it. 

 

The problem goes away once I park the car for say about 30 minutes or so, but comes right back once I drive it for a few miles.

 

Any idea why this could be happening?  

 

Thanks!

Praveen

[Spider]

Sounds like the Primary Gear pinching on the Crank.

[Dusky]

Something is pinching due to expansion. Either the primary gear on the crank, primary gear against the C clip, or the flywheel adjustment is just a hair out. Same issue on our race mini, adjusted the clutch nuts another half turn out and everything was fine.

[MiniMadRacer]

What oil are you using... not a modern synthetic one I hope..

[floormanager]

Hi,

I had something similar on my re-built engine.  I was worried that something was nipping up when warm but it turned out to be wear on the clutch pedal and just needed setting up better. As it got warm, I was not getting enough movement for the clutch to disengage properly.

 

Before your slave cylinder went, was there an issue?  Are you sure you've bled all the air out of the clutch?  Worth re-bleeding to ensure no air is trapped.  I presume yours is a verto clutch so I do not know how much movement you are supposed to get but it's over 0.5" on the slave plunger on a non-verto.

Paul

[PravSridhar]

Something is pinching due to expansion. Either the primary gear on the crank, primary gear against the C clip, or the flywheel adjustment is just a hair out. Same issue on our race mini, adjusted the clutch nuts another half turn out and everything was fine.

 

Thanks, Dusky. I also believe it needs some fine adjustment. Will be taking it in to the mechanic's next week.

 

What oil are you using... not a modern synthetic one I hope..

 

Nope, defo not synthetic! Need to check exactly which oil is in it - I only bought the car about a month ago.

 

Hi,

I had something similar on my re-built engine.  I was worried that something was nipping up when warm but it turned out to be wear on the clutch pedal and just needed setting up better. As it got warm, I was not getting enough movement for the clutch to disengage properly.

 

Before your slave cylinder went, was there an issue?  Are you sure you've bled all the air out of the clutch?  Worth re-bleeding to ensure no air is trapped.  I presume yours is a verto clutch so I do not know how much movement you are supposed to get but it's over 0.5" on the slave plunger on a non-verto.

Paul

 

Thanks, floormanager. I only bought the Mini about a month ago. The slave cylinder was the first issue I encountered. It all started with the cluth pedal starting to lose pressure and the reverse gear crunching. In a few days, the clutch pedal dropped to the floor with no pressure at all. This is when I knew the slave cylinder had packed up and bought a new one. When the slave cylinder was replaced, a complete bleed was done. 

[PravSridhar]

Good morning, folks!

 

Noticed something else. 

 

I normally take the Mini out for a 5-7 mile drive almost everyday. Yesterday, I tried the same route but decided to go very very easy on the gears (I normally throw the car around   ). I was especially gentle with the gears all through the drive.

 

Normally, by the time I come back home, 1st and 2nd gears are notchy and reverse crunches catastrophically. However, yesterday none of this happened! Even after the very same drive, all gears were slotting in perfectly and no crunching in reverse!

Edited by PravSridhar, 09 March 2021 - 07:32 AM.

[surfblue]

It does sound like a clutch adjustment issue, if you are careful you can mask the problem, slotting the gear changes in gently. If you have a workshop manual the adjustment procedure is explained and its pretty simple to do.

[Spider]

On reading your last post - what Oil are you using ?

[Miki Leyland]

Before going any further, check the oil type you are using (avoid anything different to 20W50 mineral). Chech the oil level as well.

 

I had the very same problem you describe and started thinking too much about clutches, syncros etc... until I refilled oil level to the Max (which I had been avoiding to stop a leak I had). When the engine is working and the oil is hot and splashed up inside the engine, obviously the oil level in the sump reduces, affecting gearbox efficiency... at least in my case.

Edited by Miki Leyland, 13 March 2021 - 09:28 AM.

[PravSridhar]

On reading your last post - what Oil are you using ?

 

(slightly embarassed to say) I haven't checked what oil is in the car! While I have checked the oil levels, I haven't done an oil change or a top-up. I've had the car for a few months only and it came with oil topped up.

 

Before going any further, check the oil type you are using (avoid anything different to 20W50 mineral). Chech the oil level as well.

 

I had the very same problem you describe and started thinking too much about clutches, syncros etc... until I refilled oil level to the Max (which I had been avoiding to stop a leak I had). When the engine is working and the oil is hot and splashed up inside the engine, obviously the oil level in the sump reduces, affecting gearbox efficiency... at least in my case.

 

Will check what oil is in the car and will probably also do an oil change (and fill in the oil recommended above). I am getting the clutch adjusted as well this coming weekend. Will come back with findings. 

[Spitz]

You can't really "check" what oil is in it unless you have a lab or something.  Just dump the oil immediately, filter change, add 20/50, see how it goes

[PravSridhar]

You can't really "check" what oil is in it unless you have a lab or something.  Just dump the oil immediately, filter change, add 20/50, see how it goes

 

Agreed! :) I was actually planning to speak with the previous owner to see what he had filled in. Anyway, the plan is to do a complete oil change this weekend. Will also be getting the clutch adjustment checked. Hope these two things should help resolve the issue - will keep you folks posted.

 

THANK YOU!

[Spider]

 

On reading your last post - what Oil are you using ?

 

(slightly embarassed to say) I haven't checked what oil is in the car! While I have checked the oil levels, I haven't done an oil change or a top-up. I've had the car for a few months only and it came with oil topped up.

 

Before going any further, check the oil type you are using (avoid anything different to 20W50 mineral). Chech the oil level as well.

 

I had the very same problem you describe and started thinking too much about clutches, syncros etc... until I refilled oil level to the Max (which I had been avoiding to stop a leak I had). When the engine is working and the oil is hot and splashed up inside the engine, obviously the oil level in the sump reduces, affecting gearbox efficiency... at least in my case.

 

Will check what oil is in the car and will probably also do an oil change (and fill in the oil recommended above). I am getting the clutch adjusted as well this coming weekend. Will come back with findings. 

 

 

If the oil that's in it now one of the modern slick oils or a synthetic, they will cause the gearbox to behave in this way.

A good quality Mineral Oil 20W-40 or if you do hard drive, long trips or live where the temps are higher, then a 25W-50 would be more appropriate.

There are a few oils around that are for classic cars, generally, these are quite good.