Lawson Posted October 20, 2007 Share Posted October 20, 2007 Hi All my clutch is slipping on my jimmy...However not all the time and if when it slips and i take it out of gear and then put it back in the same gear its fine again.....Is this normal...I have bought a new clutch from rex ward as i feel it must need replaceing..I have bought all the new parts.. friction lining...thrust bearing etc....All apart from the pressure plate as rex said it is very rare that they need replacing....Can anyone give me any advice on changing the clutch and on the symptoms of which i am experancing...I have a airporable dump truck so i need to take off more props i think...I have never done a clutch on any vehicle before :dunno:so any advice would be great ...Thx all Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted October 20, 2007 Share Posted October 20, 2007 It's been a while since I did one, hopefully a frequent clutch changer will give you the detail - but in the meantime this is what I remember: You only need to pull gearbox back far enough for input shaft to clear clutch (about 5"). The lower 2 gearbox bolts are taken out from inside the bellhousing - you'll see them if you take botom bellousing tin cover plate off. Clutch assy can be unbolted from same access hole, and dropped down through this also. Helps to have two of you on the job - makes it so much easier to pull back box and also put back without damaging clutch assy! Gearbox to Transfer box prop comes off, as does pto prop to tipper pump. Take out cab floor plate and put scaffold pole or similar across cab. Rope can then take weight of box while it is wangled (engineering term :whistle:) backwards. Ideally should use alignment tool (simulates the gearbox input shaft - an old one is ideal!) when fitting new clutch plate into assy, but not absolutely essential if you are very careful. If you get it wrong it will vibrate badly until corected. Not a bad job, my dad got it down to 30 minutes in the field with lime spreaders, but he did get a lot of practice!!! Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted October 20, 2007 Share Posted October 20, 2007 Lawson, Before doing anything drastic, check you have free play on the clutch pedal linkage. It may be that the clutch has worn a bit and the fingers have come out slightly and decreased the clearance. There will be an adjustable link rod adjacnt to the clutch arm on bell housing (not too familiar with GMC, but you should see it). Also, I agree with Tony (N.O.S.), except on one thing, always use an aligner to set the clutch plate centrally, without it you will struggle. True it is possible to do without, but then you have to view the plate end on and if you are only going to pull the gearbox back about 6 inches, then eyeing it up will be impossible. Richard Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted October 20, 2007 Share Posted October 20, 2007 Yes Lawson, Richard is right. I remember that we dropped the box comletely to change it for a recon box which was sitting around, as a spacing washer between 4th and 5th had broken up. Thus we could see right into assy to align it ok without the tool. Just a piece of steel shaft machined to same profile as input shaft is ok. Lime spreader drivers always carried a clutch and a broken off input shaft (because they were forever breaking off :-D) Also, with the jimmy clutch, it is not so much vibration, but the fact that if the plate (with splined centre) is not exactly right you'll struggle to get the gearbox shaft back through it! Tony Quote Link to comment Share on other sites More sharing options...
Lawson Posted October 20, 2007 Author Share Posted October 20, 2007 Hey thanks guys for all your really great advice....you have both been a real help as i am very nervous about doing the job as i will be learning as i go along.... i will check ajustment tommorow moring...and if that does not sort it i will do as you guys have said...i like the bit about the scafold pole though the cab to take the weight of the box as that was really worring me...so thanks guys... and i will give and update when the job is done.. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted October 21, 2007 Share Posted October 21, 2007 Lawson, You said it would stop slipping if you released the clutch and then let in in again, just had a thought, that the pedal linkage could be a bit stiff somewhere, go through it first before doing anything drastic. Richard Quote Link to comment Share on other sites More sharing options...
Lawson Posted October 21, 2007 Author Share Posted October 21, 2007 ok will do richard...will go though it all tomorrow morning...And once again thanks for your help....PS. would be nice if that was all it was something simple like that... 8-) Quote Link to comment Share on other sites More sharing options...
abn deuce Posted October 21, 2007 Share Posted October 21, 2007 the tm 9-801 mentions the clutch needs 2 1/2 inch free- travel with new facings .as the facings wear ,adjusting nuts on the adj.link should be backed off to maintain a 2 1/2 inch free- travel....until the lock nut is at the end of the thread then the clutch may be operated until free travel is reduced to 1 inch at which time clutch driven member assembly (with new facings) must be replaced . There is a grease fitting on the pedal shaft might need lubing or the pull back spring might be weak? Quote Link to comment Share on other sites More sharing options...
Tony B Posted October 21, 2007 Share Posted October 21, 2007 If you do get round to changing the clutch, basic saftey. 1 all bits are heavy, have good solid stands, check jacks are in good condition. 2 Don't work alone, if you get injured help may be a long way away. 3 A piece of broom handle is invaluable for holding the plate in place when you intially bolt things up. 4 use plenty of space and 5 at this time of year do it somewhere warm, cold fingers slip and get hurt. Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted October 21, 2007 Share Posted October 21, 2007 You forgot the bit about getting some beers in ready (post - job completion ONLY!) To elaborate on Tony B's most important advice - I think we used a lage trolley jack to support rear of box too (with a naughty mod. of which no more) - DO NOT RELY ON SUPPORT FROM ROPE/STRAP THROUGH CAB FLOOR ONLY, as box is heavy and it is likely to tip backwards once pulled back so far, as the support pole will not go back far enough due to seat base. Better to also get plenty of heavy timber packing under and around rear part of box, which it can be slid back on, to ensure it can't fall or roll sideways - do not underestimate the blodymindedness of gearbox to go where it wants, must weigh about 2cwt. Aligning Tool - this can be a 3-4"length of steel, diameter to just fit inside splines of clutch plate (7/8" or thereabouts), with a short length turned down at one end to fit inside nose bearing (about 7/8" long by 3/4" dia?). For how often you need it, best to trade more beers for loan of one! When undoing outer row of bolts which hold clutch coverplate to flywheel, these unscrew a long way (1/2"+) before spring pressure is relieved, so undo each bolt a little at a time, working around flywheel - this will prevent possible distortion of pressureplate. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted October 21, 2007 Share Posted October 21, 2007 Oh and one other tip from those that know ;-) Do not let the geabox drop out of line with the clutch whilst the shaft is still engaged in the clutch plate. This will distort the clutch centre and the clutch will drag, then you will have to do the job all over again :whistle: Richard Quote Link to comment Share on other sites More sharing options...
Jack Posted October 21, 2007 Share Posted October 21, 2007 Oh and one other tip from those that know ;-) Do not let the geabox drop out of line with the clutch whilst the shaft is still engaged in the clutch plate. This will distort the clutch centre and the clutch will drag, then you will have to do the job all over again :whistle: Richard Richard - think you should come down and show us exactly what you mean :whistle: :whistle: Quote Link to comment Share on other sites More sharing options...
Lawson Posted October 21, 2007 Author Share Posted October 21, 2007 Once again thank you guys for all your advice... and thanks for your good advice tony... I will not be doing it on my own...i have kevin to help me as he has fitted a few clutches to vehicles in the passed...and there is also jack there too...so i feel with all your great advice and lots of beer we should hopefully have a positive result...And if we dont ill just drink all that beer anyhow and try to forget about it all...lol....Thanks guys Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted October 21, 2007 Share Posted October 21, 2007 Richard - think you should come down and show us exactly what you mean :whistle: :whistle: Jack, If you were nearer, I would, but have a lot on at present, just take it slowly and don't take chances when pulling the box back. and leave the beers till after the jobs done, they may cloud your minds ;-) Quote Link to comment Share on other sites More sharing options...
Tony B Posted October 21, 2007 Share Posted October 21, 2007 Don't try grease or oil to ease the spline refit the ******* stuff compresses and jam, then get onto the plates. Another stupid thing. Make sure the floor is flat and can bear the weight. A trick is put a couple of 2 x 4 under the truck fixed to the floor. This ensures your trolley jacks run straight back and fore. we used a similar thing for the tractors makes life so much easier. Quote Link to comment Share on other sites More sharing options...
LeeEnfield Posted October 21, 2007 Share Posted October 21, 2007 A trick is put a couple of 2 x 4 under the truck fixed to the floor. This ensures your trolley jacks run straight back and fore. we used a similar thing for the tractors makes life so much easier. have done this trick in the past,.........It Works. :-) Quote Link to comment Share on other sites More sharing options...
ashley Posted October 21, 2007 Share Posted October 21, 2007 Quote......... have good solid stands, check jacks are in good condition. i have kevin to help me as he has fitted a few clutches to vehicles in the passed...and there is also jack there too...so i feel with all your great advice and lots of beer we best of luck best not start work untill PM for this Jack to be in good condition..... :-D :-D Ashley Quote Link to comment Share on other sites More sharing options...
Lawson Posted October 21, 2007 Author Share Posted October 21, 2007 well i have ajusted the clutch today and it has made no differance :-( so its off with gearbox and in with the new clutch...thank for everyones help :-D Quote Link to comment Share on other sites More sharing options...
abn deuce Posted October 21, 2007 Share Posted October 21, 2007 Well at least you tried everything else before diving in and then finding it was something else. I keep my fingers crossed for you that it all goes well and easily Quote Link to comment Share on other sites More sharing options...
Stormin Posted October 22, 2007 Share Posted October 22, 2007 Coincidentally I was just reading this by Dr Deuce the other day. http://www.cckw.org/clutch_adjustment.htm He seems to recommend different adjustment dimensions to those recommended above. If I was doing it I would buy a new pressure plate as well. Wouldn't want to have to go to all that work again if it's not right afterwards. Quote Link to comment Share on other sites More sharing options...
Tony B Posted October 22, 2007 Share Posted October 22, 2007 Try pastparts, they do a relining service, if you are going to the heroics of stripping it out, better to bite the bullet and plan any jobs that need doing A while engine is out B Might be worn and need replacement C need painting. It adds to the short term work but saves a lot of grief in the long run. Plenty of rustproofer on those hard to reach parts. Quote Link to comment Share on other sites More sharing options...
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