QuestionI have a 1980 Triumph Spitfire 1500 with 30000 on the odometer. Over the winter I took my 4 speed with J type overdrive transmission apart and rebuilt it with a friend from my local Triumph group. It went together well and I put it back in the car with a new clutch plate, pressure plate and throw out bairing. The gearbox shifts through the gears good when the car is not running. I have been driving the car for about 2 weeks and it appeared to be running good. I tried to downshift, but it didn't down shift very well in first and second gear, but I attribute that to the rpm's and high transition ratios. Would you recommend not downshifting? From my standpoint-- brakes are easier to replace than the gearbox.
Today there was some resistance to shift upwards into gear. It seems like I have to push the clutch pedal through the floor in order for it to shift nicely without grinding. I tried to bleed the slave cylinder, but the problem is still present. Heres the story: I try to shift into a higher gear and it doesn't go nicely, or if it goes it intermittently grinds, so when it grinds I do not push it, but let off the clutch and reapply and try a different gear and it sometimes goes and when it goes, than I return to the appropriate gear for the speed. Any thoughts? Do I have to adjust the clutch pedal? (Can I adjust the clutch pedal?)";
AnswerHi Andy,
If it shifts Ok setting still but not too well running then I believe it is in the clutch release. That seems to be a more common fault in the Spitfire and the TR-6 too. In each case I found it to be a design that required everything to be just right. I found on both cars that the clutch release was just on the edge of being enough even when they were new. On the TR-6 I was able to correct the problem by using the larger bore master cylinder as there were two sizes through the span of years. I don't think that was true on the Spitfire though. The situation is aggravated when a new disk or pressure plate is installed. If the disk is just slightly warped either by rough installation or in it's manufacturing then the pressure plate has to retract further to disengage. The Triumph factory didn't allow any tolerance here. Here is what to look at.
First, did you bleed all of the air out of the system?
Next, check the first free play in the clutch pedal (do not pump the pedal up first) measure it as accurate as you can. Then pump the pedal up several times and check it again as soon as possible to see if there is any difference. If there is a difference then you probably didn't get all of the air out which is difficult since you are trying to bleed air down. Also, did you install the slave cylinder so the bleeder is at the top and the line just below it?
Look at the clevis pin that connects the pedal to the master cylinder rod. When that pin gets worn you loose a little travel. When you rebuilt the trans. did you examine all the parts of the clutch release arm? Any excess movement in any parts of the release arm will loose travel. On one spitfire that I suspected travel of the release arm as suspect I did a test. I deformed a thick washer that the slave cylinder rod could not go through the hole. I deformed the washer with a hammer and punch on a block of soft wood so that it was shaped like a cup. I put heavy grease on the washer so it would stay in place while installing the slave cylinder and put it in the slave cylinder piston which is recessed in the center. This in effect lengthen the rod and installed the slave cylinder and pumped up the clutch and started the engine to try it. It worked well so I knew that travel was the problem. I suspected worn pins on the release arm. I didn't want to remove the trans so I then just made a sleeve that just fit over the end of the rod (so when installed it couldn't fall out of place like my washer could) I think I found a piece of fuel line off of some other car that just fit over the rod and I hammered the end closed and brazed it closed. This took care of the lose of travel due to ware in the multi piece clutch release arm. I had to adjust my end as I first made it too thick and couldn't get the slave all of the way in because the slave piston had bottomed out and stopped the cylinder from going all the way in.
The only other thing I ran into working on these cars is a bad pilot bearing in the back of the crankshaft which allows the trans input shaft to move around too much and intern moved the clutch disk out of square with the flywheel and pressure plate.
Be sure to use DOT 4 fluid too as DOT 3 will destroy the seals in the hydraulic system.
I hope this helps.
HMF
