New clutch so why does it slip! Page 1 / 4

bbbottle, Jan 13, 8:46am
i replaced the bearing,pressure plate a clutch plate in a 89 rwd van [mazda]hydro lick clutch1st izz good 2ns izz good 3rd 4th 5 th is slipping plate izz near new and other parts too! do i need to bleed clutch or is it another problem!

twink19, Jan 13, 8:49am
did you use second hand parts!

iginoi, Jan 13, 8:53am
Do you have enough freeplay in the pedal! i.e. you should be able to push the pedal a couple of mm before you feel pressure in it. It'll go fine in the low gears but more load put on the clutch / pressure plate (i.e. as the gears get higher) will cause it to slip if there's not enough freeplay.

sas777, Jan 13, 9:00am
As #3 and I'll add check out the hydraulic cylinder underneath. It could be sticking, not returning to a fully off / with a clearance position. Bleeding could help. Also was the old clutch plate contaminated with oil!

rob_man, Jan 13, 9:28am
Why do you deliberately spell 'is' wrong!

mechnificent, Jan 13, 9:33am
Appealing to his peers!

bbbottle, Jan 13, 9:50am
yeah i didspell izz wrongis this betterISbut still means the same thing[lol]txt style[lol]no free play in pedal on 3rd on wards but in one and two clutch is near floor as it should be with a new clutch etc

ladatrouble, Jan 13, 9:52am
The parts are NEARLY new!

ginga4lyfe, Jan 13, 9:55am
is it possible you managed to fit the plate in backwards! , also, maybe you should bleed the clutch system.

fordguy17, Jan 13, 10:01am
Did you machine the flywheel before fitting the new clutch!

a18a, Jan 13, 12:37pm
How long have you been driving it! A couple times after I've replaced clutches I had to take the car for a decent drive before it gripped properly

icemans1, Jan 13, 1:37pm
how long have you had a license for!

skin1235, Jan 13, 6:21pm
there is something back to front here, clutches don't hold in 1st and 2nd then slip in the rest, certainly not on a van, they just don't have the torque to do that, they will slip in the 1st and 2nd then hold in the rest
aside from that, if you've put the plate in the wrong way around it will be fouling the flywheel bolts ( and lathing them off, and not quietly either) but could give the issue you have due to not actually gripping plate material, it may be trying to function against the metal parts instead - ie fkall gripe - again it would slip and be very noticeable in 1st and 2nd rather than the others
sounds like it's time to take it out again, and do it rightwhen you put it back in

budgel, Jan 13, 6:46pm
Wrong skin1235!Clutches always slip in the higher gears first.

Think about it, it is harder work for the engine to pull a higher gear than a lower one!

clanky, Jan 13, 7:17pm
Is it possible you have put the release bearing in the wrong way round!

bbbottle, Jan 13, 8:04pm
ok clutch plate pressure plate and bearing is from a car that was used in for a bout a month then there motor blew up! so the parts i used were 2md hand but in near new condition, and no clutch plate is not wrong way round or the bearing, when i say slipping/riding in 3rd 4th etc could it be possible that it has something to do with the linkages! the clutch on the pedal is all the way out and you just touch it and thats your clutch in 3rd 4th etc 1st and 2nd is just from the floor as you would expect from a new/near new plate etc !

sr2, Jan 13, 9:01pm
Correct, it's the torque that makes the clutch slip.

mechnificent, Jan 13, 9:41pm
Strange symptom that!
Are you sure the hydraulics aren't pumping up with every consecutive use of the pedal!

mechnificent, Jan 13, 9:42pm
This is correct too by the way.

kazbanz, Jan 13, 10:47pm
--Theres no icon for dripping with sarcasm -dang

skin1235, Jan 13, 11:27pm
see I knew you guys would jump on that
but logical application does not support it, whilst you will notice a slipping clutch in higher gears more often,
the torque application is actually greater in the lower gears,
and if you could actually observe the operation of the clutch you'd find it is slipping in the lower gears a lot more than in the higher gears
you may have succeeded with your argument if you had said applied torque,
lower gears use as much or more applied torque but for a shorter time,
often they are not using max torque at all, so you don't get the sense of reving for no return in a lower gear -
unless you apply a severe load ie handbrake, and deliberately load the clutch to it's max torque - ie check the clutch
in practice the clutch appears to slip more in higher gears as you say only because it is more noticeable and our driving practices are such we do max load in the higher gears
but technically a clutch is designed to transmit the (93kw!) of engine power to a shaft,
if the loading is suffice it will not be able to transfer that power and thus slip,
and the loading is greater in lower gears than in the higher when the full (93kw!) is used in all gears


mechnificent, Jan 13, 11:48pm
You are wrong Skin and should stop digging a hole for yourself.

In the lower gears there is the advantage of the gear ratio which lowers the load on the clutch, therefore lowering the chance of it slipping. In the high gears the torque being transmitted through the clutch has to be greater to turn the axles. Apart from that, experiance allows me to say without any doubt at all that slippage will be noticed in higher gears easier and earlier.

mechnificent, Jan 14, 2:13am
Hmm, I'm not sure what point you are trying to make there Biker, but if it makes any difference, I said "load on the clutch", I never mentioned power produced.

For what it's worth, the engine produces the same horsepower, all else being equal, regardless of the gear ratio chosen.

With regards the topic being discussed though, the greater gear reduction in a lower gear, lessens the likelyhood of clutch slip.

You'd know all this though. right!

budgel, Jan 14, 2:58am
There is something odd here, the clutch pedal shouldnt behave differently depending on which gear it is in. The clutch doesnt know what gear you have selected.

If you think that the parts you fitted are OK then it must be a linkage problem. Hydraulic problems cause issues with disengagement, not engagement of the clutch as a rule.

Is there any adjustment available on the slave cylinder!

As others have said, get some freeplay happening, if it slips after that it is internal.

budgel, Jan 14, 3:19am
Biker 69, you are right in the sense that the engine power remains the same, but the load on the clutch changes depending how easy the car is to move forward.

The gear chosen is what governs how easy the car is to get moving.
If it was always the same we wouldnt need gearboxes.

Have you ever tried to start riding a tenspeed bikein one of the high gears. There is a lot more load on the 'engine' (you)'.

I wonder if the original poster could swap the slave cylinder off the original vehicle, maybe it has a different throw.

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