Think I need a new Diff and how much clutch pedal should I have?
Posted By : Nigel Gibbins, 05-Dec-2005, 07:46pm
Robert,
The diffs of the later spitfires (Mk4 and 1500) are an easy straight swap for the MK3 GT6... no worries there and you're probably right about it on it's way out (as you've described) second hand diffs though are very hit and miss and breakers like Spitbitz would suprise me if they inspected it before selling it - so you're taking your chances there. For piece of mind it's always best to get a new one... but of course there's the &163;&194;&163;&194;&163; to think about too.
A good (but not guranteed) way of checking a diff is to grab both output lugs and turn them the same way... (like it was bgin driven) the harder it is to push ike this the better it is. Also, hold one and 'rock' the other to feel for the 'lash' - how much doesn it move before you feel it at the other lug... the smaller the better. Anything close to an inch's movement then leave it well alone. Don' be surprised if you turn one output lug and the other turns in the opposite direction - this is normal.
by doing this you should get a good feel of how loose the diff is... it should be a tight as possible but you should be able to move it still. Doing this to a new diff takes a LOT of effort.
As for your clutch pedal... you should check the fluid levels as soon as possible (easy to do) and top it up if necessary (possibly bleed it through) what you are describing is indicative of the levels being a little low or contaminants in the fluid. It could also be the seals going (causing a slow leak) so if you top up and it drops again you should overhaul the hydraulic system.
The diffs of the later spitfires (Mk4 and 1500) are an easy straight swap for the MK3 GT6... no worries there and you're probably right about it on it's way out (as you've described) second hand diffs though are very hit and miss and breakers like Spitbitz would suprise me if they inspected it before selling it - so you're taking your chances there. For piece of mind it's always best to get a new one... but of course there's the &163;&194;&163;&194;&163; to think about too.
A good (but not guranteed) way of checking a diff is to grab both output lugs and turn them the same way... (like it was bgin driven) the harder it is to push ike this the better it is. Also, hold one and 'rock' the other to feel for the 'lash' - how much doesn it move before you feel it at the other lug... the smaller the better. Anything close to an inch's movement then leave it well alone. Don' be surprised if you turn one output lug and the other turns in the opposite direction - this is normal.
by doing this you should get a good feel of how loose the diff is... it should be a tight as possible but you should be able to move it still. Doing this to a new diff takes a LOT of effort.
As for your clutch pedal... you should check the fluid levels as soon as possible (easy to do) and top it up if necessary (possibly bleed it through) what you are describing is indicative of the levels being a little low or contaminants in the fluid. It could also be the seals going (causing a slow leak) so if you top up and it drops again you should overhaul the hydraulic system.
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Think I need a new Diff and how much clutch pedal should I have?
Posted By : Robert Solomon, 05-Dec-2005, 08:27pm
Nigel, thanks for the Diff advice. I really appreciate the help.
Spitbits can supply a diff from the Spitfire 1500 for about &163;85 and will give a 28 day warrenty (not a lot I know). However I've found them to be friendly and helpfull. Rimmer want about &163;350 for a recon exchange unit so I think it's worth the risk.
I'm thinking I can buy the unit before Xmas and have a good look at it before fitting it to the car. I think the plan will be to fit it between XMAS and the new year.
Like most of us I'm always strapped for cash around this time of year, I guess my car's just telling me it needs a present..
As for the clutch, I've checked the fluid levels and they are OK and no signs of leaks. I do suspect the oil is very old though. The system probably does need overhaul & new oil but taking the inside of the car out (tunnel etc.) is really a pain in the bum. (Is it me? or do you have to take the tunnel out to do almost everything on ther car?) So I think that'll have to wait until a little later.
Wish me luck. Thanks again..
Rob.
Diagnostic help required please - Maybe diff was not the problem!!
Posted By : Robert Solomon, 28-Dec-2005, 08:24pm
As previous, loud rumbling vibration got frightenly worse. The vibration was throughout the car, vibrating though the seats and up my spine. Sounded to
me like chipped teeth in the diff.
So bought a replacement diff from Spitbits. I checked that there wasn't any play between the drive shaft & propshaft inputs everything turned smoothly and with a nice amount of stiffness. When I drained the oil to replace with new the oil was very clean & thick. Took the old diff off today & replaced it with the new one. The old one leaked and was a lot looser than the new one but turned smoothly without any obvious grating. I began to worry.
Finished this evening & took the car for a test drive, full of hope & expectation that I'd solved the problem..
Guess what....No change vibration still there! Feeling really confused and pi**ed off now.
p.s. while car was jacked up I rotated the wheels and everything seemed OK, no wheel bearing play.
These are the symptoms, does anyone have any suggestions what the problem might be?
Start the car no problems tick over OK engine sounds sweet as a nut. Put car in 1st drive off and serious vibration shakes the whole car. Change gear and vibration occurs in all gears & with o'drive. Frequency & loudness does change with engine revs.
Put foot on clutch or take car out of gear while going along and vibration goes away. Take foot off accelerator and cruise/coast & vibration lessens. Put foot on cluthch & rev the engine while moving & engine still sounds super. There's no cluthch judder or slippage.
Tomorrow I' going to take the propshaft off & check the UJ's. Does anyone have any better ideas? (p.s. my propshaft has a jubilee clip around it at the diff end. Is this normal? why's it there? Is it used to ballance the prop shaft?)
I can't believe both diffs had the same problem.
Please help, any suggestions will be gratefully received...
So bought a replacement diff from Spitbits. I checked that there wasn't any play between the drive shaft & propshaft inputs everything turned smoothly and with a nice amount of stiffness. When I drained the oil to replace with new the oil was very clean & thick. Took the old diff off today & replaced it with the new one. The old one leaked and was a lot looser than the new one but turned smoothly without any obvious grating. I began to worry.
Finished this evening & took the car for a test drive, full of hope & expectation that I'd solved the problem..
Guess what....No change vibration still there! Feeling really confused and pi**ed off now.
p.s. while car was jacked up I rotated the wheels and everything seemed OK, no wheel bearing play.
These are the symptoms, does anyone have any suggestions what the problem might be?
Start the car no problems tick over OK engine sounds sweet as a nut. Put car in 1st drive off and serious vibration shakes the whole car. Change gear and vibration occurs in all gears & with o'drive. Frequency & loudness does change with engine revs.
Put foot on clutch or take car out of gear while going along and vibration goes away. Take foot off accelerator and cruise/coast & vibration lessens. Put foot on cluthch & rev the engine while moving & engine still sounds super. There's no cluthch judder or slippage.
Tomorrow I' going to take the propshaft off & check the UJ's. Does anyone have any better ideas? (p.s. my propshaft has a jubilee clip around it at the diff end. Is this normal? why's it there? Is it used to ballance the prop shaft?)
I can't believe both diffs had the same problem.
Please help, any suggestions will be gratefully received...
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Diagnostic help required please - Maybe diff was not the problem!!
Posted By : John Davies, 28-Dec-2005, 08:45pm
Jubilee clip! Ah HAH!
Elementary, my dear Robert.
A unbalanced propshaft may be restored to balance by the use of two jubilee clips, the screw drives of which act as counterweights. The idea is that you keep one still and rotate the other, testing each time until the imbalance goes away.
ONE clip? "It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth" said Holmes. The second one has fallen off.
John-
Diagnostic help required please - Maybe diff was not the problem!!
Posted By : Robert Solomon, 29-Dec-2005, 10:33pm
Thanks for clue John,
Took propshaft off, removed jubilee clip, changed both u/j's and refitted prop shaft.
While car was on stands with wheels off ground, started engine & put in gear. Used a plank of wood to brake each wheel in turn (allowing other to rotate freely = no nasty noises or vibration.
Took car for test drive and ...........
Problem solved! vibration cured.
Only problem now is I couldn't get exhaust off & sheared a nut off exhaust manifold joint. So had to remove inside of car to get at front propshaft u/j. Got to put it all back together again tomorrow.
Isn't working on these old cars fun? How do I get rid of all this black grease under my nails?
Christmas jobs tally = chassis welded, new alternator, replacement diff and new propshaft u/j's...Please god I hope she runs nicely for while now.
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Diagnostic help required please - Maybe diff was not the problem!!
Posted By : John Davies, 29-Dec-2005, 11:39pm
Robert,
I thank you.... (pause for applause)
Actually, you are a bit of a hero if you got the propshaft off and back again without removing the carpets, gearbox cover etc. Doing so from underneath is only for masochists.
As for removing the oil - the old army advice is best, for what to do when 'in the field' with only one sheet of toilet paper. Fold twice into four, tear out the middle and keep, put your finger through the hole and .... no, I can't go on it's too horrible for a 'family' website, but you use the torn off middle to clean under your fingernail.
If less heroic, rub soap under the fingernails BEFORE oily job.
John-
Diagnostic help required please - Maybe diff was not the problem!!
Posted By : Ian Mulford, 30-Dec-2005, 01:56am
I tried telling friends of mine the old army technique too... problem was it was at the dinner table... they didn't seem to see the funny side
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Diagnostic help required please - Maybe diff was not the problem!!
Posted By : Colin Wake, 30-Dec-2005, 10:08am
Now you can either remove the subsequently proven un-necessary replacement diff, refit the original and then try for a refund with Spitbits on the replacement, or if no refund, sell the replacement, or even sell the original I suppose, but you are selling a small part of the orginal heart of your car.
Colin-
Diagnostic help required please - Maybe diff was not the problem!!
Posted By : Don Cook, 31-Dec-2005, 06:28pm
What a wonderful Xmas tale!
As for poo paper...use both sides!
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