Preverto 1275 clutch actuation issues
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I had a HECK of a time getting my clutch to work properly. The biggest oversight was the ball at the end of the arm. I went to a muffler shop and had them add metal back to the end. Then I got TOO much throw. I ground it down and it was too short again. I bought parts from a hardware store and made an adjustable pushrod. I used an eyelet with threaded shaft, a threaded bolt (1.5" long) and a section of threaded rod. I closed the eyelet down by removing a section of it, heating it and bending it to fit the clevis pin perfectly. I welded the threaded nut to the threaded rod then cut it to length. Hope I haven't lost you yet. In the end I bled out the system and made tiny adjustments until it was at the exact position to the floor and made for smooth shifting.
The ball on the end of the arm, the plunger hole and the push rod all wear out. It's easy to overlook any or all of them. Good luck on your quest. Poor transmission, hope you figure it out soon.
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When pushing the slave piston back into the bore use a piece of hose into a clear bottle with some brake fluid in it and when you release it it will suck the fluid back into the cylinder which should help keep the air out of the system.
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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Sometimes, a small air bubble can form at the bleeder end of the slave. Even after extended bleeding the bubble can remain and the fluid just flows around it.
So after a few goes at bleeding, remove the slave rod to clutch arm clevis pin.... and the spring.
Open the bleed valve
Push the slave pushrod/piston (by hand) gently into the slave... you'll (maybe... probably??) see some bubbles/fluid flow out of the valve. Keep pushing until no more air appears (or the piston runs out of travel).
Close bleed valve.
Have assistant gently push the pedal until the slave push rod can be connected back up. You may have to open up the clutch adjustment gap.
Once everything is connected up try another bleed sequence - which should result in no bubbles...
And you should be good to go....
Cheers, Ian
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Your friendly local Minishop might have pointed out that your old clutch arm is indeed a proper Mini item albeit slightly modified - no doubt to accommodate the normal wear in the rest of the mechanism. There was absolutely no reason to replace it... (other than profit for the guy you bought it off).
Don’t know where you got the advice re the 1/8” gap. Its wrong .. forget it.
So,as per the original advice.... remove the nuts and try again.
If the clutch still drags (grinds) take the rubber seal off the end of teh slave cylinder, have attractive assisitant press pedal to floor and check whether the slave piston is running into the C clip at teh outer end of teh slave bore.
If it is, replace the new clutch lever with the old one and you should be right.
Cheers, Ian
https://www.7ent.com/pages/article-easy-pre-verto-clutch-adjustment.html
actually it's her car, she also bought the haynes manual - but it wasn't much help either.
thanks for the advice, we'll check it out
is there an official service manual? this car is slightly a basket of unknowns. honestly, I wouldn't even have known anything was wrong with the clutch arm or thought of replacing it if her service shop hadn't mentioned it.
So ... as I'm getting tired of saying... just get rid of them... or wind them out of the way.
I'm thinking "her service shop" is not 7 .....???
I measured my slave bleeder .. its 7/16th .. a 10mm spanner is too small. But then its old and more modern replacement parts might be different. The slave cyl. in not a uniquely Mini part.. other cars use versions of the same (Lockheed) product. Mine came off a 80/90s GM product and was fitted because it has a slightly small bore .. giving a touch more travel. The GM and Leyland bits "look" the same. But I wouldn't worry ... the important part is "how far does the top of the clutch are move when you floor the pedal" ?? Have you measured it ... and is it something like 15/16th"???
IMHO the main problem is that people expect parts made up to 50 odd years ago (when did they swap to the verto clutch??...late 70s??) to not wear and for parts made by a range of aftermarket companies to still fit and work exactly as the designer intended. When parts don't work as intended one has to work out why and make whatever adjustments are required. Setting things to factory (or maybe not) specifications just doesn't take into account the variations and tolerances that have built up over time....
You pays your money and takes your chances..
Cheers, Ian
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depending on what your 'new' arm is made of, it can be bent if heated with an oxy acetylene torch setup. put the bottom end in a large vise and once heated, put a pipe on the upper side and give it a slight tug. If it's the same material as the oem part, you won't need to get it cherry hot, just red hot. Caution, don't over bend it.
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But shifting with the engine running was a problem. It turned out that the stock return spring was too strong. I replaced it with a lighter spring and have no issues. These clutches seem to be unforgiving.
1976 1000 (Current Project)
1975 1000 Donor
1969 Cooper (Future Project)
1971 Opel GT
1972 Corvette Stingray
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Your friendly local Minishop might have pointed out that your old clutch arm is indeed a proper Mini item albeit slightly modified - no doubt to accommodate the normal wear in the rest of the mechanism. There was absolutely no reason to replace it... (other than profit for the guy you bought it off).
Don’t know where you got the advice re the 1/8” gap. Its wrong .. forget it.
So,as per the original advice.... remove the nuts and try again.
If the clutch still drags (grinds) take the rubber seal off the end of teh slave cylinder, have attractive assisitant press pedal to floor and check whether the slave piston is running into the C clip at teh outer end of teh slave bore.
If it is, replace the new clutch lever with the old one and you should be right.
Cheers, Ian
https://www.7ent.com/pages/article-easy-pre-verto-clutch-adjustment.html
actually it's her car, she also bought the haynes manual - but it wasn't much help either.
thanks for the advice, we'll check it out
is there an official service manual? this car is slightly a basket of unknowns. honestly, I wouldn't even have known anything was wrong with the clutch arm or thought of replacing it if her service shop hadn't mentioned it.
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Your friendly local Minishop might have pointed out that your old clutch arm is indeed a proper Mini item albeit slightly modified - no doubt to accommodate the normal wear in the rest of the mechanism. There was absolutely no reason to replace it... (other than profit for the guy you bought it off).
Don’t know where you got the advice re the 1/8” gap. Its wrong .. forget it.
So,as per the original advice.... remove the nuts and try again.
If the clutch still drags (grinds) take the rubber seal off the end of teh slave cylinder, have attractive assisitant press pedal to floor and check whether the slave piston is running into the C clip at teh outer end of teh slave bore.
If it is, replace the new clutch lever with the old one and you should be right.
Cheers, Ian
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Slacken those nuts off and see if you have enough clutch travel.
If you have enough at that point have someone hold the clutch to the floor and tighten the nuts up until they touch the cover then back them off slightly, they are there to prevent the clutch overthrowing itself which is a near impossible thing to do with a Mini clutch.
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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Original questionable setup, that ran "fine":
https://pix.sfly.com/2Uzyvq
Questionable components replaced with pre-verto factory hardware:
Gap adjusted to 1/8" according to haynes manual:
https://pix.sfly.com/cDY0eg
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But , yes... Alex has good advice. My interpretation of the video is that the stop nuts seem to be stopping full travel of the clutch arm. You will need about 15/16th travel at the top...
Without the spring there's no need for the standard clutch adjustment. While this is not universally endorsed procedure .....without the spring, the clutch becomes "self adjusting".
Don't understand "I've adjusted the clutch pivot travel to 1/8"...." And I can't see where you are measuring travel but an eighth doesn't sound much.... do you mean 1/8 travel for the release bearing carrier??? (I've not ever measured this).
And..."I also disengaged the limit the stop so ignore that, too..." ???? If this refers to the overthrow nuts then it renders the video pretty useless...
Sooo, leave the spring off, remove the overthrow nuts and let us know how you get on....
Cheers, Ian
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Take off the overthrow stop nuts (the big ones on the plunger).
Take the return spring off the top and trhow it away.
Pull the arm out so that the release bearing makes contact with the diaphragm and wind out the adusting bolt till it touches the arm. Back it off by one flat.
Try again.
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Prior to putting the stock pivot arm and clevis pins, the transmission operated fine. But our local mini shop suggested the unknown arm setup be replaced with the proper one.
After installation, we either grind or have to severely force the gear shifter.
The transmission has no problems moving between gears when the engine is off
Troubleshooting:
I've adjusted the clutch pivot travel to 1/8"
Bled the slave
I've swapped between the old rod and new rod
With an 1/8" of an inch of travel shouldn't that be enough travel to disengage the transmission?
Here are some images of the setup. I took the return spring off for the moment so ignore that.
I also disengaged the limit the stop so ignore that, too.
https://youtu.be/2YWBVhArKwA