I am running a 1916 with twin webbers on a 1300 swing axle gearbox with 31x 10.5 tyres on my baja and my clutch seems to be slipping under load when changing gears. I think i might need a heavier pressure plate but i'm not really sure. Any ideas?

Thanks.

hey mate, the combination of 1916 with 31's still running the swing axle 200mm clutch will be abit of a drama, i have heard of people running a heavier pressure plate to compensate and ended up working so i think your on the right track!!.

I had a 1916 with twin webers and the stock 200mm clutch / pressure plate combo. It was fine. Don't go to a heavy duty unit, you'll just break your gearbox

Do you think it could be just a case of a stretched clutch cable? coz it's adjusted nearly all the way out and i dont know how old the cable is?

The cable will have nothing to do with it unless its adjusted incorrectly.
You should have approx 5 - 10mm play at the TOP of your clutch lever at the bellhousing from the point of where it naturally sits on the cable to pulling it foward by hand and feeling it touch the pressure plate.
If you have no movement at all you will be riding the clutch full time which is causing the slipping and wearing out the thrust bearing.
If you have the required free play , sorry but ya better pull the motor and check the flywheel , pressure plate , and clutch for wear etc and post your results.

Andrew

How old is yours - is it worn out?

The clutch, pressure plate and throwout bearing are all new but the cable is not. Thanx andrew that sounds about right as i don't have any play i dont think. i'll check it out on the weekend and post my results.

You definitely need some free-play as Andrew said. The best play to measure the play is at the pedal. You should be able to feel 20-30mm of freeplay in the pedal (where it is lightly sprung). The clutch take-up point should not be at the very end of the pedal travel (just before the pedal is released completely).

If the cable is fine, then you may have a flywheel that is too worn / has been machined too many times. The deeper the recess in the flywheel is, the weaker the pressure plate will seem.

An oil leak from the gearbox input shaft will also cause slipping and other issues.

Is it a major job to replace that seal? I did notice it was a little oily when i pulled the old engine out but i didn't think much of it coz that engine was leaking so bad anyway. Oil just about everywhere.

It's easy to replace once the engine is out. I normally replace it every time I have the engine out because it's so cheap and easy to change then (as opposed to later). Just carefully dig it out either with a screw driver, or by screwing a screw into it and then pulling it out with pliers (just be careful not to damage the gearbox hole or input shaft seal surface).

Also don't forget that o-ring in the flywheel, it always catches me out

cheers, it turns out it is not adjustment so it must be something more. i'll be pulling the engine out this week sometime to fix it. I had the flywheel off to get it machined and i don't remember seeing any o-rings? is it in the flywheel or the engine case?

Did you have the flywheel resurfaced?

If it gets resurfaced too many times it will become too deep, and lowers the pressure plate pressure.

I did get it machined. i don't know how many times it has been before though. is there a minnimum depth? as in measurement?

The o-ring is in the flywheel where it goes over the end of the crankshaft.

Hmmm, i should check that.

Are you in Brisbane? There are a couple of good clutch shops around. Where did you buy the new clutch and pressure plate from, and what brand is it?

My VW manuals don't say anything about tolerances for the flywheel. But it does say the maximum amount to be skimmed off the pressure plate is 1.0mm.

A good clutch specialist can shim the pressure plate spring to account for this type of problem.

When does it slip, only on full power when driving hard changing gears, or even when driving normally changing gears?

Yeah i'm in brisbane, it's ok when you baby it. If you just ease the power on its ok but when you put your foot down it slips. but very rarly in first. Put it this way, i could be cruising at about 70 kph and then i put my foot down and it slips, same at 100kph you get my drift? and also when i change gears driving hard. mainly under load, the more weight i got in the car the worse it is. and it doesn't happen all the time. most of the time but not all. I got the clutch and pressure plate from mick motors, i think it was sachs. i'll find out on friday when i pull the engine out.

If the clutch is soaked in oil its pretty much useless right?

If the clutch is wet with oil you can clean the the pressure plate with kero or turps etc but DO NOT clean the clutch plate with anything but hot soapy water or water based degreaser , although i would probabley not re use the clutch plate and just keep it as a spare as you can purchase clutch plates only for not many dollars .
By the way how long has this clutch kit been in the car and did it do it before the clutch change plus when installing the new clutch kit did you remove the film of protective laquer from the new pressure plate face as if this was not done then this will be you problem as the clutch plate is only griping on the fly wheel side and sliping on the laquer on the pressure plate face.
If this is the case once you have removed the motor and clutch , wipe the face of the pressure plate down wth some thinners and lightly scuff up the pressure plate side of clutch plate with some 120grit sand paper.
Let us know what it all looks like when you pul the motor Sat morn

dont forget when machinng the flywheel that the clutch surface and the surface that the preasure plate bolts up to
have to be machanie the same amount or you will be weakening the preasure that the preasure plate can put on the clutch i take an extra 0.5mm off the preasure plate surface to give it a bit more bite works well all mine have it done to them.
And if the clutch is a lukct brand or somthing like that they are crap i bought one put it in and it slipped straight up on a 1600 find a sachs one

Clutch has been in the car for about 3-4 months i guess. yeah i took the coating off. I can't remember if it was doing it before the clutch change as i only drove it on the test drive and then home from where i bought it. I think i would have noticed if it was though. i had clutch shutter problems when i first put it in but that was fixed by machining the flywheel and a new bowden tube. i've got another flywheel i can try if i have to. i'll probably need to get it machined though. Why is it that i always leave these little problems till just before i go to the beach in my cars? Does everybody do this or just me? First new engine went into manx just before straddie, Kadrons, new engine cage and new exhaust on manx day before valla, Next New engine in manx went in day before it was a wedding car at tweed heads for my brother. now this? I'm going to ballina for christmas in it.

Trust me you are not the lone soldier when it comes to last minute builds as i am well known for it my self, how about this for a little pressure .
This week ~
Its my 40th Sat Night 1st Dec
We're renovating our house and have tilers starting 7am monday morning and haven't pullled up the carpet or vynal yet
My parents arrive from Tassie tomorrow night and are staing with us WITH THEIR DOG SO WITH OUR TWO DOGS THAT MAKES 3
A few mates are flying in for the weekend for my party so got to do the right thing and entertain them.
I can't take any time of work due to a high pressure job at the Airport
And i'mm still trying to finish the Baja Kombi flat 6 Subie engine conversion for Christmas
No pressure at all really NOT !!!!!

That's some pretty bad slipping your describing, it's certainly not normal. I think you'd have to have an oil leak or something to get that problem. Can you see anything leaking from between the bellhousing and engine? There is a little gap at the bottom where it is designed to leak (instead of filling the bellhousing.

I think there might be a bit leaking from there. its hard to say though. Iv'e been to lazy to have a proper look and whenever i degrees the engine i only do the engine, i just turn a blind eye to the gearbox. Will know on saturday i hope.

Well i got it up on the hoist and the clutch is dry, no oil leaking and it seems to have fixed itself. I could not get it to slip at all today. Is it possible that the clutch may have needed to bed in a bit after adjusting? other than that i have no idea??? i'm stumped???

Kiss your bible...or your VW service manual!

It hasn't completely fixed itself... she still slips sometimes. today it's good, tommorrow it might be different! i love volkswagens!