ausmini
https://www.ausmini.com/forums/

Very heavy clutch
https://www.ausmini.com/forums/viewtopic.php?f=2&t=35928		 Page 1 of 1
Author:  sgc [ Thu Sep 20, 2007 10:43 pm ]
Post subject:  Very heavy clutch
OK, so a while back I changed the clutch plate in my warm 1152 and since putting it all back together, the clutch pedal has been much harder than it was previously. The only changes were the friction plate and thrust/release bearing, but now the pedal is disturbingly hard, and also slow to engage.

The slave cylinder is new, with a new seal. The master is not, but before the change the pedal weight was normal. The hose is probably reasonably old. I have a good return spring fitted.

I've bled the system thoroughly, but that didn't help.

It feels very much like a hydraulic restriction -- it takes more effort to disengage the clutch, and it is slow to reengage which causes slippage under power after a gearchange... but with reduced backpressure on the slave cylinder (i.e. unbolted from the car and separated from the clutch arm) the pedal is quite light which casts doubt on that theory.

Has anyone here had this problem? Any suggestions as to the possible causes? My greatest concern is that the increased pressure required to disengage the clutch will cause premature excessive crank float, and I'd kinda like to avoid that :shock:
Author:  KLAS [ Thu Sep 20, 2007 11:05 pm ]
Post subject: 
sounds like a problem i had over here with a verto clutch
the friction plate's tooth ring that match the primary gear, what ever its called, was poorly machined that it couldn't move at all. you could press the pedal once and the clutch wouldn't engage again.
even heard of some that wouldn't fit the primary gear at all, all were made by the same manufacturer
Author:  brett [ Fri Sep 21, 2007 12:40 pm ]
Post subject: 
don't know much about mechanics, but you could use it to build up your leg muscles :lol:
Author:  sgc [ Fri Sep 21, 2007 1:41 pm ]
Post subject: 
Yeah, I'm not afraid of a heavy clutch per se.. otherwise I wouldn't have a Mini :lol: :lol: The thing that gets me is that the clutch is slow to re-engage when you take your foot off the pedal, which it never used to do. That, coupled with the weight of it makes me suspect something ain't quite right... I just can't for the life of me figure out what that is. :? :?
Author:  Anto [ Fri Sep 21, 2007 2:24 pm ]
Post subject: 
I would be fixing this problem as soon as possible - a heavy clutch is pretty normal on a Mini, but it should not be slow to return, the clutch diaphragm should make it return quickly. Sounds like something is binding somewhere, first up I would pull the clutch arm off and check for anything amiss, but it is sounds like something internal which will necessitate pulling the clutch apart. Maybe the diaphragm isn't square, or the bolts aren't seated properly which would buckle the drive straps and could cause the drag you're experiencing - but if this had happened you would probably have significant clutch shudder as well. This is largely conjecture as you wouldn't know until you've pulled things apart.

By the way, when you depress the clutch do the engine revs drop?
Author:  sgc [ Fri Sep 21, 2007 2:35 pm ]
Post subject: 
Anto wrote:
Sounds like something is binding somewhere, first up I would pull the clutch arm off and check for anything amiss, but it is sounds like something internal which will necessitate pulling the clutch apart.


Yeah, that's my suspicion. The clutch arm came off and was thorougly cleaned, lubed and reassembled when I changed the friction plate, so it's unlikely to be that.

Anto wrote:
Maybe the diaphragm isn't square, or the bolts aren't seated properly which would buckle the drive straps and could cause the drag you're experiencing - but if this had happened you would probably have significant clutch shudder as well.


No clutch shudder at all, it's just slow to return which lends to slippage after a quick gearchange.

Anto wrote:
By the way, when you depress the clutch do the engine revs drop?


Nope, not that I remember.

The only thing I can think is Klas may be close and the friction plate is binding on the primary gear. That didn't get any grease when things went back together, but I really wouldn't have expected that to make such a massive difference. I don't remember which brand it was, but I think it was reputable -- B&B, or PBR, or something like that. Whatever Autobarn supply in their rebuild kit ;)
Author:  Anto [ Fri Sep 21, 2007 2:40 pm ]
Post subject: 
You aren't supposed to grease the clutch splines anyway. I've never had any problems with clutch splines on cheaper clutch drive plates, except when they separate themselves from the rest of the plate, but that wouldn't cause the problems you're experiencing :D

Also I would still not totally disregard that the clutch hose could be knackered, if it is old or unknown it may be worth just changing it anyway.
Author:  sgc [ Fri Sep 21, 2007 2:43 pm ]
Post subject: 
Anto wrote:
Also I would still not totally disregard that the clutch hose could be knackered, if it is old or unknown it may be worth just changing it anyway.


Yeah, that's an unknown. I have a nice new shiny braided item which will go on next week 8) 8)
Author:  Morris 1100 [ Fri Sep 21, 2007 7:04 pm ]
Post subject: 
It is the hose. Don't bother looking at anything else, it is the hose. 8)
They swell up internally and eventually block up completely. You can press it and fluid will go through but with a very hard pedal and then it will only return slowly.

But think about it... If your clutch hose is stuffed, how are your brake hoses? 8)
Author:  DOZ [ Fri Sep 21, 2007 7:17 pm ]
Post subject: 
I agree that its most likely the hose. I had one that was split internally and didn't look like anything was wrong.

Daniel
Author:  jbeenz [ Fri Sep 21, 2007 7:20 pm ]
Post subject: 
yea, change the hose, i learned this lesson the expensive way! new master $130, new slave $45, skinned knuckles - pita, still no clutch. new hose $24, problem solved. many wasted hours.
Author:  drmini in aust [ Fri Sep 21, 2007 7:26 pm ]
Post subject: 
What they all said ^^^, I had this prob too. :wink:
Author:  sgc [ Fri Sep 21, 2007 8:37 pm ]
Post subject: 
Awesome guys, thanks for the replies. I was basically down to two possibilies -- either the hose is knackered, or the friction plate is binding on the primary gear splines. Strange that the hose would fail all of a sudden following a disassembly/reassembly of the clutch though.. :?:

Like I said before, I've got a nice shiny new braided hose to go on the car, so I'll fit that next week and report back.

Morris 1100 wrote:
But think about it... If your clutch hose is stuffed, how are your brake hoses?


The brake hoses have all been done reasonably recently, so they're fine. I'm doing a disc conversion next week either way, so they're getting changed again with brand new braided hoses 8) 8)
Author:  sgc [ Sat Sep 29, 2007 11:06 am ]
Post subject: 
Guys,

You bloody legends! Changed the clutch hose this morning and gave it a thorough bleed, and I've never felt such a smooth clutch pedal on a Mini. Not too heavy, not too light.. perfect. Haven't driven the car yet, but standing still the clutch action is sweeeeet. 8) 8) 8)

Thanks for the tip, bloody brilliant.

-- Simon
Page 1 of 1 All times are UTC + 10 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/