Clutch not working under aggressive acceleration

 Created by: jbelow2
   Forum Width:     Forum Type: 

 Posted: Jul 3, 2019 02:07PM
Total posts: 8085
Last post: Jul 20, 2019
Member since:Feb 7, 2006
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Quote:
Originally Posted by jbelow2
I do not think it is a slip condition as it always .. jumps right to it..  The 4 gear stall is successful..

The clevis pin behind the clutch pedal looks to have some play.   I will  get a new one soon..

One thing i noticed is the clutch return spring bracket was tilted back toward the slave cylinder, when I straightened it out by adding washers to the pivot pin which holds the slave cylinder rod, the clutch doesn't work at all the pedal goes to the floor with no resistance.  There is no visible movement of the slave cylinder plunger rod.  If I remove the spring, the plunger rod move just a very small amount.

I also tried to bleed the slave cylinder today, and only get spits if of air and oil..

The master cylinder looks original.  I has a metal canister and not a plastic.   

I am betting the oil is passing the internal piston on the master cylinder.   

Could this be my problem?

Can these be rebuilt?
John




Did you look behind the dust seal on the slave cylinder, if it is wet you need a new slave cylinder and replace the hose while it is off.
If the master cylinder is bad it will drip fluid off the end of the clutch pedal inside the car, if that is dry look at the slave cylinder.
The master and slave cylinder can be rebuilt with varying results, for what they cost i would replace them.

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.

 Posted: Jul 3, 2019 01:08PM
Total posts: 12
Last post: Jul 3, 2019
Member since:Apr 18, 2016
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
I do not think it is a slip condition as it always .. jumps right to it..  The 4 gear stall is successful..

The clevis pin behind the clutch pedal looks to have some play.   I will  get a new one soon..

One thing i noticed is the clutch return spring bracket was tilted back toward the slave cylinder, when I straightened it out by adding washers to the pivot pin which holds the slave cylinder rod, the clutch doesn't work at all the pedal goes to the floor with no resistance.  There is no visible movement of the slave cylinder plunger rod.  If I remove the spring, the plunger rod move just a very small amount.

I also tried to bleed the slave cylinder today, and only get spits if of air and oil..

The master cylinder looks original.  I has a metal canister and not a plastic.   

I am betting the oil is passing the internal piston on the master cylinder.   

Could this be my problem?

Can these be rebuilt?
John




 Posted: Jul 3, 2019 12:05PM
Total posts: 8085
Last post: Jul 20, 2019
Member since:Feb 7, 2006
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
All good points to check posted by others but i also don't think you have a slipping clutch problem.
It sounds like the slave hose may be closing up internally, it lets the fluid flow when the clutch is pressed normally but when it is depressed fast the fluid is not flowing fast enough to release the clutch and it does not disengage.
Look for leaks on the slave cylinder behind the rubber dust cap and have a friend press the clutch while you look at how much throw on the arm you have.
Try it with normal pressing and the fast pressing of the clutch to see if the rod acts differently.

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.

 Posted: Jul 3, 2019 11:02AM
Total posts: 8206
Last post: Jul 20, 2019
Member since:Aug 14, 2002
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
CA
The description you give suggests the clutch is not releasing. i.e. not a slipping problem.
Check the nuts on the clutch plunger in the middle of the clutch cover (aka "wok"). With your foot off the clutch pedal, there should be a minimum gap between the nuts and the clutch cover. Too little and your clutch will not fully disengage. Check also that the plunger is not binding, and the clutch throw-out arm is not worn excessively where it goes into the plunger or that its pivot pin is not worn. Check also that floor matss etc are not restricting the clutch pedal range of movement.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jul 3, 2019 10:56AM
Total posts: 1449
Last post: Jul 19, 2019
Member since:Apr 30, 2009
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US

  I dont see 'slipping' as a description to your problem.


Another Test ..

Double pump the clutch before the 'agressive ' shift. 

  Under a 'slower deliberate clutch push, it could be engaging enough and work OK.. under the 'fast shift' its not quite moving enough fluid to dis engage just enough... causing this mis shift.

   -  if a quick double pump of the pedal helps the shift problem likely air in the hydraulic system, because you're moving 'more fluid quickly.


Also check the freeplay in the clutch lever arm... too much free play (between the wok and the 1/4 inch bolt)  requires too much throw by the hydraulic system and failure to disengage the clutch when depressed.

 Goodluck.

 Posted: Jul 3, 2019 09:07AM
Total posts: 6741
Last post: Jul 9, 2019
Member since:Feb 26, 1999
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
wanna test the clutch for slipping?   Start the engine, put it in 4th with your foot firmly on the brake and straddling the gas pedal.  Release the clutch while feeding it gas and holding the car with the brake pedal.  Car should stall out immediately. If it continues to run, it's likely your clutch disc is contaminated and is slipping.

Your issue sounds more like an internal leak or a simple bleed the system fix.

Bleed the system at the clutch slave. If that doesn't cure your ills, I'd replace the clutch m/c.

 Posted: Jul 3, 2019 08:52AM
Total posts: 12
Last post: Jul 3, 2019
Member since:Apr 18, 2016
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
Hi all, It's been a while since I have posted and after a lengthy search of the forums,..  I think I need some help.

I have a pre-verto 1978 mini. I believe 1098 engine...

3 years ago I replaced a ring gear (which works great) during that time of having everything apart, I replaced the clutch, pressure plate, and plunger, bearing, and clevis pins..

I am not exactly sure how to explain it,  I have noticed that when we drive normally and modestly everything works fine, but when I want to get on it a bit with a little more aggressive acceleration, and when I press the clutch it releases, but when I go to shift,,  it just grinds gears and it will not go into any gear.. And i have to bring the car to nearly a stop to get it back into gear.

I am not sure if this was present when we bought the car, or if it is due to the clutch replacement.

I am live in Ohio, 43440

Thanks in advance.