clutch piston wear

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nyabinghi

clutch piston wear

Post by nyabinghi »

so, my clutch is becoming inoperable - i've replaced the piston oring, but the pin and bearing are totally worn out. i honed the clutch cover, and tried cleaning/repacking bearing, but the brass pin is worn down so much it don't spin freely, which causes oring to loose it's seat.. any one have any ideas where i can get a clutch piston/bearing/pin assembly - maybe online somewhere?
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paso750
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Post by paso750 »

you will note if you check your dealer that the parts for a Paso are really expensive as you can only get the whole piston/bearing assembly as a complete.

I changed the secondary piston* and bearing with one of a 750SS (early model). The bearing might have been a replacement SKF, I can`t recall. This piston doesn`t have an O-ring gasket but a V-type one which doesn`t make any difference (afterall it`s probably better). It fits perfecty. The upper edge where the bearing is positioned in is about 1mm lower compared to the Paso piston, but that doesn`t have any impact. You have to remove the seal and put the bearing instead (SKF 608-ZZ). (The mushroom pin in the middle fits perfectly)

The advantage is that the SS piston is available as a single part for a reasonable price. I got this hint from my Duc dealer who helped me out more than once with interchangeable parts from other Ducs.

I`m using it for years now and it works fine.

The SS cylinder is: 195.2.002.1B

(the spring is 799.1.012A for the SS and 0665 16 440 for the Paso, but I think I kept my old one from the Paso)

Check the prices at your local Duc dealer and please post them as I don`t remember the price difference.

Gerhard

*note the original piston has 26mm diameter, there are identical looking covers i.e. from the 750F1 which piston has 27,95mm diameter. Better measure before ordering something ! (the 27,95mm piston has the Ducati # 066516450)
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paso750
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Post by paso750 »

I don`t know about the availability of the pin(mushroom). It might be part of the piston/bearing set. However I guess you can find a shop who can machine it. Looking at the shape I don`t think that`s a hard job to do for a pro.
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Post by Rodney »

I recently replaced the piston and pressure plate, the piston was worth a fortune but the pressure plate was resonable. i think the piston bearing assembly was AU$240+gst and the pressure plate about AU$100 (which is a modified version of the original no little bearings or springs). they are still available from Ducati just at a price!!!
i purchased mine through Scott Walker Motorcycles Brookvale.

Rodney
Ducati ST2 2002 , Ducati 696 2010 , Ducati Pantah 1983 (in progress )
jfiore
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Clutch Piston

Post by jfiore »

I can vouch for Gerhard's information. I replaced the original clutch slave piston assembly with the assembly from the '91 750SS. I used the part numbers that Gerhard provides for reference, and had no problem ordering the part (it cost me $200 US two years ago). I found it at a local (Connecticut) Ducati shop, Moto-Fixx. The only problem is that the piston does not come assembled, and the roller bearing for the rotating release pin has to be pressed into the piston body, so you will need a small shop press of some kind.

FYI, the clutch disk set from the '91 750SS also fits the Paso.
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Post by paso750 »

there seem to be huge price differences. I paid much less for the piston only (in Germany). I would have to ask for the current price.

Gerhard
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Clutch Piston

Post by jfiore »

Although the price I paid seemed high for what was in the package (piston, rotating pin, roller bearing, ball bearings, piston outer seal, inner seal for the pin), I was so happy to find a replacement part that I paid.

If one of the members of this forum had access to a machine shop, it would not be very difficult for them to reproduce the parts of the assembly - I'm sure that there are quite a few Paso owners who would be very interested in buying new parts!
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Post by paso750 »

Hi,

I have to correct myself. The number of the piston I mentioned is correct, but it`s not from a 750SS but from a 900SS w. dry clutch (91-97) (and younger according to my mechanic).
This clutch is operated from the opposite side of the engine, however the piston fits.
We checked the numbers today. For the Paso, 750SS etc there`s either the whole set (incl. bearings etc) or the bearings, O-ring a.s.o. as a single part. But not the single piston. This is only part of the (expensive) set. For the 900SS it is available as a single part and costs - tada - €25 ($45 in the US). Use it with its V type rubber ring, don`t use the old O-ring for it.
The history of the parts program showed that the ordering number changed so there`re 3 numbers.
The one mentioned before (195.2.002.1B), one ending with 3B instead of 1B and the latest 19590023B.

Sorry for this little mix-up. We changed this piston about 2,5 years ago or so.
Image
remember to remove the blue seal, put in a bearing (SKF 608-ZZ) instead and use your old mushroom pin (not sure if you have to switch the spring with the old one from your bike, but I would as the part number of the spring is not the same). The bearing btw is commonly used for inline skates or skateboards so you may find it also in a sports shop.

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G.

PS: there is also a repair set for the early 750SS/900SS with dry clutch and secondary piston (26mm) in the clutch cover. Its number is 19520011B and it costs € 118/$175. It is the replacement for 19520011A & 037016460. 037016460 was the part number of the P750 clutch piston. This repair set is the complete piston with seal, bearing and pin (below right).
If you need the piston only or don`t see the point why to spend 3,5x as much get the 19590023B + new bearing (approx. $3-5) and use your old spring and mushroom pin. (even if you have to get a new bronze pin machined by a shop it will be the cheaper option)

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Re:

Post by fasterdammit »

paso750 wrote:remember to remove the blue seal,


I did this just a year ago, so you'd think I'd remember what I did... But I don't. How to get that stupid blue seal out of the slave? I've already poked myself good once; I figured I better ask someone who knows better before I need stitches. ;-)
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Re: clutch piston wear

Post by higgy »

:banghead: or an eye
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There's no problem so bad that a little fixing can't make it worse! : )
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Re: clutch piston wear

Post by Mc tool »

I made a mushroom thing out of an 8mm brass bolt ( with 10mm + shank , thread length not important ) , chucked the bolt in my drill press and used a file to put a bit of radius on the bolt head, trimmed it to length so about 1mm longer than the width of the bearing ,fitted to bearing, peened the end over so it doesn't come out of the bearing and then fitted bearing to a 97 900ss clutch slave piston ( after removing blue seal ) :)
I wish I was young again............Id be heaps smarter than last time
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Re: clutch piston wear

Post by paso750 »

Jake, the blue oil seal should just lever out. If there`s no seal/o-ring on the piston you can try to heat the piston up a bit and then lever the blue seal out. Otherwise just drive a sharp screw into the blue seal and pull it out. The problem then will be how to hold the piston ;)
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Re: clutch piston wear

Post by fasterdammit »

paso750 wrote:Jake, the blue oil seal should just lever out. If there`s no seal/o-ring on the piston you can try to heat the piston up a bit and then lever the blue seal out. Otherwise just drive a sharp screw into the blue seal and pull it out. The problem then will be how to hold the piston ;)
That's what I thought I did last time, but this one was giving me fits. I was kind of anxious about marring the surfaces on the piston to, so I wasn't using grips or a vice or anything - just trying to hold it in one hand.

Ok, so just perseverance & brute force? I have those. ;) Thanks, G!
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Re:

Post by fasterdammit »

paso750 wrote:use your old spring and mushroom pin. (even if you have to get a new bronze pin machined by a shop it will be the cheaper option)
Did somebody draft up the specs on the mushroom pin at one point? I seem to recall seeing a mechanical drawing for it, but I'm drawing a blank. I think mine's had it; I'm hoping the local shop could reproduce one for me ...
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Re: clutch piston wear

Post by paso750 »

see P750 FAQs
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