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Andyinthegarage
V4 Fanatic
United Kingdom
361 Posts |  Posted - 05 Jul 2012 : 21:56:11  
| I want to experiment with shims between the pressure plate and the flywheel which I believe is possible to achieve with the engine still in the car.
I read that it is possible via the inspection cover, but has anyone ever tried?!? |
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pchristy
V4 Guru
United Kingdom
1790 Posts | Posted - 05 Jul 2012 : 22:03:27
| Er, why?
--
Pete
"Duct tape is like the Force: It has a light side and a dark side, and it binds the Universe together!" |  |
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Andyinthegarage
V4 Fanatic
United Kingdom
361 Posts | Posted - 05 Jul 2012 : 22:29:04
| Clutch operates fine, but all the way down at the end of the pedal travel. If I shim the slave cylinder, the slave piston just repositions and back to square 1 again.
I suspect that there is wear in the pressure plate arms, but don't feel like taking the engine out again just now so....
If I lift the pressure plate away from the flyweel by say 1mm, the clutch will disengaged 1mm earlier equating to considerably more than 1mm reduction in travel of the pedal before separation.
As I will remove the shims from behind the slave cylinder at the same time, I should avoid contact between pressure plate and release bearing actuating lever allowing the pedal to safely travel beyond the separation point.
Simples!.....in theory.
And an amusing experiment. | |
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Woody
V4 Guru
United Kingdom
2878 Posts | Posted - 06 Jul 2012 : 01:21:40
| Do-able but awkward, via the vent shield at back of bell-housing. Use a hammer shaft to lock the pressure plate from turning while the bolts are removed/replaced. Difficulty is getting shims in place and putting bolt through. An extendable magnet probe might be useful. Hope you have good eyes, I would struggle. I am assuming it is a standard F&S clutch rather than a VW clutch.
Interested to see what the ultimate effect is. | |
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pchristy
V4 Guru
United Kingdom
1790 Posts | Posted - 06 Jul 2012 : 09:29:10
| OK, I can see where you are coming from, but as Woody says, it will be extremely difficult, and you *really* don't want to drop anything while you are doing it!
It's not unusual for the pedal to be nearly at the bulkhead before a new clutch dis-engages, but this will quickly settle in. My 96 has a diaphragm clutch, and I've just fitted a new Sachs clutch in my 95. In both cases the clutch works fine without the need for any shims behind the slave cylinder. The diaphragm one does have some thin ones under the pressure plate, I seem to recall, but these are part of the fitting kit.
Are you sure your hydraulics are in good order and there is no air in the system? I had to replace the seals in my 95 last year, and used an Eezi-Bleed to bleed it. It made a big difference, and would certainly be easier than trying to shim a pressure plate in situ.
Its also worth checking that you actually have the right master and slave cylinders! In view of the age of these cars now, who knows what bodgery they have undergone in the past......!
--
Pete
"Duct tape is like the Force: It has a light side and a dark side, and it binds the Universe together!" | |
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melle
V4 Guru
United Kingdom
4145 Posts | Posted - 06 Jul 2012 : 10:01:12
| If it disengages OK without scratching, I would leave it. If you stand on shimming the pressure plate, 1mm will be too much I'm afraid. I would take the engine out again, check the release bearing arm for wear and check with a ruler if the pressure plate lies even. You might need different thickness shims (I always use 0,1 and 0,2mm).
1970 96V4 "The Devil's Own V4"
1977 95V4 van conversion project
1988 900i 8V | |
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TTruckie
V4 Fanatic
United Kingdom
320 Posts | Posted - 06 Jul 2012 : 14:42:43
| | I think you will be asking for the clutch to slip?! | |
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melle
V4 Guru
United Kingdom
4145 Posts | Posted - 06 Jul 2012 : 14:52:31
| If he'll use 1mm shims, yes.
1970 96V4 "The Devil's Own V4"
1977 95V4 van conversion project
1988 900i 8V | |
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Andyinthegarage
V4 Fanatic
United Kingdom
361 Posts | Posted - 07 Jul 2012 : 01:15:54
| Thanks guys.
Yes, I know I am just asking for slippage, and this IS a new friction plate, so perhaps it will settle with wear, just felt like a challenge!
I'll take a squint through the inspection hole and see if I can achieve in place.
From what has been said though it sounds awkward!
Perhaps I should just wait until I take the engine out again and fit a new pressure plate - I lazily fitted a new friction plate with the old pressure plate. | |
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Andyinthegarage
V4 Fanatic
United Kingdom
361 Posts | Posted - 07 Jul 2012 : 01:21:55
| Oh yes, forgot to say - Hydraulics are in v good nick, original but refurbished master and slave and pressure bled.
It is a standard clutch with the three mountings and six bolts mounting the pressure plate to the flywheel. | |
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rsimps
V4 Guru
United Kingdom
1616 Posts | Posted - 10 Jul 2012 : 07:53:46
| | You really need the engine off the box. There is a measurment in the Saab manual from clutch to release bearing face, unfortunatly all the Haynes type manuals seem to forget to tell you about this. You should use the shims on a new clutch to set this distance. | |
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Andyinthegarage
V4 Fanatic
United Kingdom
361 Posts | Posted - 11 Jul 2012 : 18:01:23
| I am aware of the 17mm depth measurement for flywheel face to friction surface, but anyone know what the release bearing to pressure plate distance should be?
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jdt
V4 Fanatic
United Kingdom
340 Posts | Posted - 12 Jul 2012 : 21:30:00
| There seems to be a lot of clutch problems but I have only ever used standard clutches with uprated coil springs on my rally car with no issues
There does seem to be problem with replacement friction plates being too thick for direct replacement without checking the measurements which I believe is where most of the problems stem from
The release bearing contact face on the pressure plate should be roughly flush
If it is below the face of the pressure plate then the friction plate is too thick aand you need to shim the pressure plate as rsimps says.
you need thin washers as a standard 8mm washer will probably be too much
It is a fiddle to fit them through the inspection hole but totally possible and a lot less work than removing the engine, if you drop anything it will just fall to the bottom and not do any harm
If you are still short of travel then put a washer or 2 behind the slave cylinder to compensate for wear in the release arm, if you go too far you will hear a nasty noise as the springs contact the release arm and you should have done the step above first
The adjustment bolt acts in a different way and cannot compensate for wear - you just need to have a few mm clearance so the release bearing is not in contact with the pressure plate
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Andyinthegarage
V4 Fanatic
United Kingdom
361 Posts | Posted - 15 Jul 2012 : 15:12:40
| Thanks all for the advice. After taking off the inspection cover and squinting thru' using a complicated arrangement of old wing mirrors and torches, I have come to inevitable and cowardly conclusion that I'll leave it until I take the engine out again this winter.
I am convinced that it is feasible to shim thru' the inspection cover, but not realistic on the drive, in the rain, in between DIY jobs.
Thanks again anyway. | |
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OWEN
V4 Fanatic
United Kingdom
319 Posts | Posted - 16 Jul 2012 : 00:16:30
| I've done this.
It's impossible to see what you're doing but it's easy to do it by feel. As somebody pointed out if the shims are too thick then the clutch will slip. That's what's happening with mine now so I've now got to remove the shims and replace with thinner ones. Rather than use washers for shims in the first place I should have made them up with tabs on them so that I'd have something to grip when removing them. Now I've got to try to remove them with some hooked wire and hope that if I drop them they do make their way to the bottom of the bell housing and stay there rather than into the clutch mechanism. It's a bit of an awkward job but removing the engine isn't always practical at the side of the road........I used 1mm shims originally. I intend to replace them with less than 1/2mm.
I actually think that a lot of clutch problems are to do with wear on the yoke/fork that holds the release bearing. If that's worn just 1mm then all the dimensions on the whole clutch will be out. | |
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Andyinthegarage
V4 Fanatic
United Kingdom
361 Posts | Posted - 16 Jul 2012 : 19:23:32
| So, with two bolts per "leg" of the pressure plate mounting, I assume you remove one, slacken the other, slip in the washer, replace that bolt but slightly slack, remove the other one, in with the washer, tighten both and then rock the engine round to the next one?
That's a Ninja test using nothing but feel, and presumeably "The Force".!!
Against my judgement, you have me intrigued again! | |
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| | Topic | |
Shimming Clutch Pressure Plate
