27 replies to this topic

[mini_pooper]

 Hi all! 

 

I have just finished a 3 year restoration of my 1981 Mini HL to Mk1 look from the ground up, and aside from some cosmetic finishing inside the car, it’s more or less ready to go. I do however have an issue with the gear change which I hope you all can help with:

 

Things to bear in mind before reading through the symptoms list below:

- The Gear mechanism is a Rod Change type and clutch is Pre-Verto.

- The engine and gearbox were completely stripped and rebuilt with new parts as necessary by a successful mini racer in Norway where I lived for about 3 years until 3 months ago. Wear in either unit (engine or gearbox) is unlikely since they have only driven about 30 miles since the refurb and the guy who built them up is known for being very precise with his work.

- All mounts are new and sound (top and bottom arm steadies are poly), with no splitting or tearing.

 

On to the Symptoms:

1) Difficult to engage 1st and 2nd at standstill (also when engine is off), almost like there is a gate blocking the gears.

2) Shift from 1st to 2nd usually gives a “klunk” when 2nd is engaged as if it "hooks" the gears together

3) Nine out of ten times, 3rd to 2nd is not possible without double de-clutching with a throttle blip to match revs.

4) In some cases, when going from 3rd to 2nd, double de-clutching will not work and then the only way to get it into 2nd gear is by stopping, then moving the gear lever between where 1st and 2nd should be until it finally goes into one of those two gears, at which point it then also goes into the other gear as well.

5) Sometimes, when trying to change gears, it is almost as if there suddenly are no synchros in ANY gear. You push the clutch in and the revs fall to idle (indicating the clutch releases), but then when trying to engage any gear, all you are met with is grinding like on a non-synchro first gear box when not double clutching. When this happens, not even double de-clutching and rev matching works (note that I don’t continue to grind the gears, I stop the car and do what I have written in point number 4 until I can get it back into gear).

6) Especially when reversing, but sometimes pulling away in first, the car will judder as the clutch is released as if there is oil on the plate, but there is no evidence of oil under the clutch housing (note however the housing has not yet been off to inspect the plate).

7) When in slow traffic and crawling in 1st gear, when you go to press the clutch in to come to a stop it is almost as if the clutch does not disengage smoothly/gradually with the pedal press. Rather, it suddenly “pops” off in the last third of the pedal's travel, releasing the engine, resulting in a jerk/klunk from the front (imagine slowing right down in gear until the engine almost stalls and then suddenly, quickly pushing the clutch pedal in to free it off to release the engine, that’s what it feels / sounds like).

 

It would seem like points 1-5 are shift related and points 6-7 are clutch related, although of course they could all be caused by the clutch or something else. I have adjusted the clutch, but apart from raising the bite point on the pedal to a more comfortable location, it made very little difference in helping the symptoms listed above.

 

The system has been bled by a workshop that helped me get the timing and carbs correct so it is unlikely (but of course still possible) that this is the issue. The master cylinder is new and slave cylinder had all seals replaced (bore was good and there is no fluid getting past the bore seal.

 

I still have to check that I have not fitted the shifter eyelet under the gear stick upside down which could make it hard to get into gear, but I can't imagine this would also cause grinding on it's own? Another thing I will do is fit new roll pins inside the gear lever housing as there are currently bolts that are a bit loose fitting for my taste allowing wasted movement that should go directly to twisting the rod for gear selection. Could this help alleviate some of the engagement issues? The sleeve on the rod by the gearbox has the quick release roll pins and has very little slack so I am happy with that end of the rod   

 

As you can imagine after 3 years of blood, sweat and tears, it is really demoralising that I can’t finally get to enjoy the car   

 

Any help and tips is appreciated! I have listed as much as I can put together (maybe a bit too long, sorry!), but if you have any questions that I can answer to help diagnose this, fire away!   

 

It would also be great to know if there are other Mini folks in the North East Lincolnshire area! Specifically Cleethorpes!   

 

All the best,

 

John S

 

Edited by mini_pooper, 29 July 2017 - 08:35 PM.

[nicklouse]

return stop set to 15 thou?

 

arm movement an slave point at least 1/2"?

 

remove clutch arm and check each pivot point for wear. so the pins and the arm and the push rod. then look at the ball on the end of the arm for bending and/or wear.

[mini_pooper]

return stop set to 15 thou?

 

arm movement an slave point at least 1/2"?

 

remove clutch arm and check each pivot point for wear. so the pins and the arm and the push rod. then look at the ball on the end of the arm for bending and/or wear.

 

Will check all these things to be sure. Return stop was adjusted which raised the bite point but double checking never hurts and will do this at the same time I check the arm movement.

 

I assume the clutch arm just comes out when the pins are removed?

 

One thing I forgot to mention - the shaft holding the two large nuts on the clutch adjustment, there is some rotational movement of that shaft, maybe 1/8th of a turn, is this correct?

 

John

[Spider]

Was the Primary Gear replaced or Re-bushed?

[nicklouse]

 

return stop set to 15 thou?

 

arm movement an slave point at least 1/2"?

 

remove clutch arm and check each pivot point for wear. so the pins and the arm and the push rod. then look at the ball on the end of the arm for bending and/or wear.

 

Will check all these things to be sure. Return stop was adjusted which raised the bite point but double checking never hurts and will do this at the same time I check the arm movement.

 

I assume the clutch arm just comes out when the pins are removed?

 

One thing I forgot to mention - the shaft holding the two large nuts on the clutch adjustment, there is some rotational movement of that shaft, maybe 1/8th of a turn, is this correct?

 

John

 

there is always some movement as it is only the arm that stops any rotation.

[mini_pooper]

Was the Primary Gear replaced or Re-bushed?

 

From what I understood when I spoke to him after the rebuild, everything was taken apart and anything that was at all worn was replaced. Of major parts, he replaced one axle and one bearing, everything else was sound.

 

Would be strange if the primary gear was not re-bushed when it was all out anyway?

 

I did not have these issues before the rebuild, but when he was doing the engine anyway I asked him to do the 'box too

[mini_pooper]

 

 

return stop set to 15 thou?

 

arm movement an slave point at least 1/2"?

 

remove clutch arm and check each pivot point for wear. so the pins and the arm and the push rod. then look at the ball on the end of the arm for bending and/or wear.

 

Will check all these things to be sure. Return stop was adjusted which raised the bite point but double checking never hurts and will do this at the same time I check the arm movement.

 

I assume the clutch arm just comes out when the pins are removed?

 

One thing I forgot to mention - the shaft holding the two large nuts on the clutch adjustment, there is some rotational movement of that shaft, maybe 1/8th of a turn, is this correct?

 

John

 

there is always some movement as it is only the arm that stops any rotation.

 

 

Oki doki, that's good news then 

[tiger99]

The two large nuts are the overtravel stop adjustment. Start by loosening them off. Then set the adjusting bolt, the one that contacts the arm, to get 15 thou clearance when the arm is pulled back against the spring.

Now, pedal fully down, nip up the overtravel stop adjuster by hand until it just contacts the casing, then 2 flats more (some say half a flat, it is not all that critical) and tighten its locknut.

I am guessing from what you have said that you have adjusted the overtravel stop instead of the adjuster, which would explain all your symptoms as the clutch would not be disengaging fully. Apologies if I am wrong.

[mini_pooper]

The two large nuts are the overtravel stop adjustment. Start by loosening them off. Then set the adjusting bolt, the one that contacts the arm, to get 15 thou clearance when the arm is pulled back against the spring.

Now, pedal fully down, nip up the overtravel stop adjuster by hand until it just contacts the casing, then 2 flats more (some say half a flat, it is not all that critical) and tighten its locknut.

I am guessing from what you have said that you have adjusted the overtravel stop instead of the adjuster, which would explain all your symptoms as the clutch would not be disengaging fully. Apologies if I am wrong.

 

Hi Tiger 99,

 

I adjusted the clutch using the procedure you mentioned (loosen the large over travel stops, then adjust the stop bolt halfway up the arm, then the larger stop nuts to end the process). I am going to re-adjust again to be sure it is correct and that it is all as I left it.

 

Got a tip from a friend who told me to start the car on a level road where it will not roll, put it in first and keep the clutch pedal to the floor with all brakes off. If the car starts to move after a short while then I am looking at the clutch master or slave seals losing pressure and "re-engaging" the clutch by itself.

 

I have read about people having issues with new units / seals before so I will give this a go too, but it is a fiddly job if this turns out to be the case!

 

- J

[nicklouse]

a lot safer just to press the pedal and have someone watch the clutch arm. or video it for about 5 mins to see if it returns if you don't have someone to watch it and don't want to get one of those pedal pressing leverthings used to apply the brakes when doing the alignment.

[mini_pooper]

a lot safer just to press the pedal and have someone watch the clutch arm. or video it for about 5 mins to see if it returns if you don't have someone to watch it and don't want to get one of those pedal pressing leverthings used to apply the brakes when doing the alignment.

 

Was just thinking about this and how I can rig a camera so that I don't have to leave the car running while I wait and also to avoid unnecessarily stressing the release bearing just to test this 

[Rorf]

Could be a multitude of problems here - too much end float on the crankshaft, primary gear not freely turning on the crankshaft, gearbox main shaft incorrectly assembled, clutch pressure plate incorrectly set up, gear selector assembly incorrectly assembled, drop gear clearance too tight.Looking at the pic of of the engine compartment the rebuild looks immaculate so would hope the internals are just as immaculate and the problem turns out to be something very simple. Good luck

[mini_pooper]

Could be a multitude of problems here - too much end float on the crankshaft, primary gear not freely turning on the crankshaft, gearbox main shaft incorrectly assembled, clutch pressure plate incorrectly set up, gear selector assembly incorrectly assembled, drop gear clearance too tight.Looking at the pic of of the engine compartment the rebuild looks immaculate so would hope the internals are just as immaculate and the problem turns out to be something very simple. Good luck

 

Thanks Rorf,

 

Hopefully it will not be anything internal.

 

I can't see the guy who built this box up doing these things wrong, but I'm always keeping it in mind. He races minis, rebuilds his own units and the car is one of the most successful racers in Norway (his car, not mine   ). He started working with the mini dealerships in the 70s or 80s and has worked with these cars since.

 

Would be strange to make mistakes, but of course, I'm not ruling anything out until I've checked. If after all the easy to check / fix / replace items still haven't fixed the issue, I will have to go deeper!

 

My main suspect for the engagement issue is the looseness of the bolts being used in place of the roll pins in the gear lever housing giving too much play. It might cure that issue (getting it into gear), but the grinding issue probably isn't related to that, more likely to be the clutch?

 

Will work systematically through everything 

Edited by mini_pooper, 19 June 2017 - 02:33 PM.

[nicklouse]

the roll pins can be bad but don't really produce the problems you mention.

just go through the points already mentioned. start with the leak test then measure the travel then dismantle and clean inspect replace (if needed) lube and replace.

[mini_pooper]

the roll pins can be bad but don't really produce the problems you mention.

just go through the points already mentioned. start with the leak test then measure the travel then dismantle and clean inspect replace (if needed) lube and replace.

 

Will do - start with the free stuff, it's always cheaper 

 

Re roll pins - at the moment there are none in the lever gear housing, just bolts in place of them that are probably 1mm too skinny. Way too much movement so I'll replace them anyway with proper roll pins.

 

- J