Huey Posted May 25, 2008 Report Share Posted May 25, 2008 Hi all, I have spent a number of weeks trying to sort out my TR4 clutch. I have read thru the forums and CD and can't find anything similiar for the 4. Basically the problems is I have pump the clutch a couple of times to get it to engage. I have bled it numerious times and even resorting to the TR6 method of pushing the slave cylinder back while bleeding to remove trapped air (non found btw). If I am driving in traffic with numerious clutch engagments it works ok, only playing up after a period of 5 minutes or so. Is this an adjustment issue or is something in the wrong place... I have attempted to adjust the rod but it appears I can not get enough rod adjustment to take up all the slack. I am right in thinking the adjustment for 0.1" clearance relies on being able to bottom out the slave cylinder? As I don't appear to be able to do this it leads me to think: 1. The slave cylinder is on the wrong side of the atttaching plate (mine is as depicted in the manual ie. slave flange on engine side) 2. The operating rod is attached to the wrong hole on the lever (mine is on the botttom hole as depicted in the manual) 3. The rod is too short although it looks original. Please give me some guidance as i am unsure which way to good without confirming the correct set up. My car is up on jacks at the moment so will be able to provide some quick feedback. Thanks in advance Quote Link to post Share on other sites
PILKIE Posted May 25, 2008 Report Share Posted May 25, 2008 Hi Huey. I am pretty sure that what you describe is partial master cylinder seal failure,it works when you pump it fast and use it when changing gear away from standing, but after a bit of driving in top, when you need to change down,its lost its pressure and you have to pump it up again for it to work! Its probably the seal thats kaput,but it maybe a scored bore that is the culprit. Easy and cheap to replace the master,or overhaul it with a seal kit. Myself,I would replace it, then overhaul the faulty one at your leisure and keep it as a spare! Let us know what transpires!! Good luck Dave Quote Link to post Share on other sites
Huey Posted May 25, 2008 Author Report Share Posted May 25, 2008 Hi Dave, Thats what I thought, so have replaced both within the last month, I had previousily (last 6 months) resealed them but have had this problem since I brought the car in 06. So unless there is a fault on reseal (possible) and same fault in replacement master (unlikely) I didn't think it was a hydraulic problem. If i can confirm that my TR4 is correctly set-up I think I will have remove the new master cylinder and check the seals. Huey Quote Link to post Share on other sites
PILKIE Posted May 25, 2008 Report Share Posted May 25, 2008 (edited) Hi Huey. When was the clutch itself replaced? do you know its history? What about the slave to master connecting hose? is it rubber? "could be its ballooning inside", or is it solid plastic? If the clutch has worn down,it will be difficult to engage unless the pedal is pumped up, even then it will be at the floor when you engage! Wiil be easier when in motion but difficult when stationary or changing down! Could be a bent clutch bearing fork! At worst a problem in the gearbox affecting the synchro ring gears. I had to replace a mates rover 2000 p6 gearbox as he had horrendous engagement problems,we bled it over and over!!,no good! We checked all the external gear linkages,slave and master seals,All came to the result the box HAD to be the problem! When I took out the box to put a known good replacement one in, I found the mainshaft had broken where it was bolted to the flange thats connected to the prop,this caused excess movement of the gear mechanism causing it to be out of alignment for easy gearchanges. Good fault hunting!! Dave Edited May 25, 2008 by PILKIE Quote Link to post Share on other sites
Huey Posted May 25, 2008 Author Report Share Posted May 25, 2008 The hose is a new braided one, but I don,t know the history of the clutch. In all other aspects of gearbox and clutch are fine, only the initial pumping. I am a optismist so don't think it is more than clutch trouble!. Huey Quote Link to post Share on other sites
RandallD Posted May 25, 2008 Report Share Posted May 25, 2008 I hate to bring this possibility up as it involves a bit of work, but perhaps you have a broken clutch fork pin. With that you will get play in the fork and erratic behavior such as you describe. I'm not clear on how to diagnose, perhaps others can eliminate this as a possibility as it does mean pulling the transmission. Randy 64 TR4 Quote Link to post Share on other sites
Tr4Tony Posted May 25, 2008 Report Share Posted May 25, 2008 Huey It sounds very like you may have the slave cylinder bracketry incorrectly assembled so that youre not getting the correct engagement. There is a good exploded view in the workshop manual, so check this out carefully. The rod should be long enough. You may have duff cover which is fractionally too thick (check this if its a Laycock as there were a batch of duff NOS covers on the market) or the bearing carrier is the wrong type and is holding the fingers just off the bite point. Ive had this trouble mixing clutch parts and gearboxes, so check the external stuff first as this is probably the most likely source of the problem. Regards Tony Quote Link to post Share on other sites
Tr4Tony Posted May 25, 2008 Report Share Posted May 25, 2008 Huey It sounds very like you may have the slave cylinder bracketry incorrectly assembled so that youre not getting the correct engagement. There is a good exploded view in the workshop manual, so check this out carefully. The rod should be long enough. You may have duff cover which is fractionally too thick (check this if its a Laycock as there were a batch of duff NOS covers on the market) or the bearing carrier is the wrong type and is holding the fingers just off the bite point. Ive had this trouble mixing clutch parts and gearboxes, so check the external stuff first as this is probably the most likely source of the problem. Regards Tony Quote Link to post Share on other sites
knapman Posted May 25, 2008 Report Share Posted May 25, 2008 (edited) Huey When you push the rod on the slave cylinder manualy you should have minimal play before you can hear the thrust bearing connecting inside the clutch housing. If there is a lot of play there is something assembled wrong. As previously mentioned the taper pin could be sheared & all your doing is taking up the play all the time,also is the cross shaft bearings in good condition, any play in them can give problems. My slave cylinder is connected in the middle hole of 3 on the lever, not sure if its correct but it works for me. Bob K Just looked at my slave cylinder & its the reverse of the manual IE the other side of the bracket, in fact i have a 1/16 inch spacer in between them. Not saying its correct but it works. I do have a different engine but that shouldn't make a difference. Hope you sort it. Bob Edited May 25, 2008 by knapman Quote Link to post Share on other sites
Huey Posted May 25, 2008 Author Report Share Posted May 25, 2008 Bob As you explain, it appears to me that i cannot take all the play out of the system, because the rod will not bottom out the slave piston. I have had a look at the manual page 2.103 (fig 3) and 2.106 (fig 6) both of these show exactly the way my slave cylinder is set up. If the slave will fit the other side of the bracket I believe it will allow me to adjust the rod so i can set the clearence correctly, I would like to confirm what is correct before I rip it all apart. If the taper pin is sheared surely I would have a constant inability to engage the clutch no matter how much you pump the peddle. Quote Link to post Share on other sites
knapman Posted May 25, 2008 Report Share Posted May 25, 2008 (edited) In theory your right about the taper pin but i think sometimes it can sheer & jam on cross shaft. I think its probably the hydraulics tho. Have you recently changed either cylinder or both? There are 2 different sized cylinders, .7 & .75dia If the master is .7 the slave .75 it wont have enough capacity to fully push the slave the full movement. As i mentioned my slave is the opposite of the manual. Was all this working OK before you stripped it all down & are you using the original parts that were on it or have you changed anything? Bob Just a thought, have you stripped & rebuilt the master cylinder, when i did mine i made a mistake of fitting the pushrod retaining washer the wrong way round (where the circlip is). It has a domed middle around the hole, this caused the slave not to return fully causing the bearing to be constantly engaged. The later push rods you couldn't dismantle so couldn't make this mistake. Took me months to discover! If you have an adjustable rod on the master cylinder make sure you have a little play in it when not under pressure also that the pin & holes are not worn giving excessive play. Everything has to be exact on these clutches or you will have problems. Edited May 25, 2008 by knapman Quote Link to post Share on other sites
Huey Posted May 25, 2008 Author Report Share Posted May 25, 2008 In theory your right about the taper pin buti think sometimes it can sheer & jam on cross shaft. I think its probably the hydraulics tho. Have you recently changed either cylinder or both? There are 2 different sized cylinders, .7 & .75dia If the master is .7 the slave .75 it wont have enough capacity to fully push the slave the full movement. As i mentioned my slave is the opposite of the manual. Was all this working OK before you stripped it all down & are you using the original parts that were on it or have you changed anything? Bob Just a thought, have you stripped & rebuilt the master cylinder, when i did mine i made a mistake of fitting the pushrod retaining washer the wrong way round (where the circlip is). It has a domed middle around the hole, this caused the slave not to return fully causing the bearing to be constantly engaged. The later push rods you couldn't dismantle so couldn't make this mistake. Took me months to discover! the hole It so long ago i cannot remember if it was like this when i brought the car. and can not remember how it was assembled. I had been putting the pumping down to air, then after a great deal of bleeding confirmed none in the system. I changed the master because it was leaking from the pipe connection (stripped threads) and changed the slave on advice that it must have had a damaged bore. The symptoms have been the same all the way. I checked the master bore diameter it is 0.75" same as the old one. I have just found this on the moss site: "There are three holes in the clutch cross shaft arm on all 4-cylinder Triumphs. The slave cylinder's push rod fork should always be connected to the middle hole, the other two holes being present for use on different Triumph models. However, the top hole, if used, would increase clutch travel relative to pedal movement, but with quite an increase in pressure at the pedal." I will adjust my rod from the bottom to the middle and see what happens......... i don't have an adjustable rod at the master cylinder so can discount that Quote Link to post Share on other sites
knapman Posted May 26, 2008 Report Share Posted May 26, 2008 Huey Do you have the bracing bar fitted between the slave bracket & sump bolt to prevent movement also the 2 return springs, one on foot peddle & one between bottom of lever & slave bracket? When its all connected push lever with hand & adjust rod to give 1/8" play. Bob Quote Link to post Share on other sites
Huey Posted May 26, 2008 Author Report Share Posted May 26, 2008 HueyDo you have the bracing bar fitted between the slave bracket & sump bolt to prevent movement also the 2 return springs, one on foot peddle & one between bottom of lever & slave bracket? When its all connected push lever with hand & adjust rod to give 1/8" play. Bob Bob I do have the brace and all the springs, I have now moved the rod to the middle hole. I have taken her out for a drive and she is much better. Although there still is too much travel, it doesn't require pumping. I still can not get the correct clearance so to confirm, do you mean push the lever so the piston is forced back into the slave cylinder, if so I still run out of rod before the piston bottoms out. Quote Link to post Share on other sites
knapman Posted May 26, 2008 Report Share Posted May 26, 2008 Huey When you push lever/rod out, as if activating clutch you should have 3/16 to 1/8 slack before thrust bearing connects to clutch. If you listen carefully you can hear the bearing contacting clutch. The external spring should pull lever back into slave cylinder when released. At the master cylinder end you should have about 1/16 slack in peddle lever before it activates the cylinder. Check for wear in the pin & hole. Every bit of wear adds up to loss of travel at slave end. Bob Quote Link to post Share on other sites
Dick Posted May 27, 2008 Report Share Posted May 27, 2008 Try removing the return spring to see if that makes a difference. Also do you know that your master cylinder is the correct piston diameter.......if it is too small you will not get sufficient displacement to move the slave cylinder far enough......I have known people to fit small diameter master cylinders in an attempt to lighten the clutch. Regards Dick. Quote Link to post Share on other sites
johnny250 Posted May 27, 2008 Report Share Posted May 27, 2008 (edited) This is one way to overcome clutch problems, as seen at TRGB, and fitted successfully to my car too...... john Edited May 27, 2008 by johnny250 Quote Link to post Share on other sites
Huey Posted May 27, 2008 Author Report Share Posted May 27, 2008 Try removing the return spring to see if that makes a difference. Also do you know that your master cylinder is the correct piston diameter.......if it is too small you will not get sufficient displacement to move the slave cylinder far enough......I have known people to fit small diameter master cylinders in an attempt to lighten the clutch. Regards Dick. Dick Didn't think about leaving the spring out, I will give that ago...... I have double checked the diameter of the bore 0.75" on the new and old one. Thanks Huey Quote Link to post Share on other sites
Huey Posted May 27, 2008 Author Report Share Posted May 27, 2008 This is one way to overcome clutch problems, as seen at TRGB, and fitted successfully to my car too...... john Hmm.....interesting. Assuming there is no problem moving the slave to the other side of the bracket i think something similiar would allow the correct adjustment of the operating rod. The only think is why is it this way? as all the figures in the workshop manual show the setup of the slave exactly as my car? Huey Quote Link to post Share on other sites
johnny250 Posted May 28, 2008 Report Share Posted May 28, 2008 Hmm.....interesting. Assuming there is no problem moving the slave to the other side of the bracket i think something similiar would allow the correct adjustment of the operating rod. The only think is why is it this way? as all the figures in the workshop manual show the setup of the slave exactly as my car? Huey I think the main reason is because some of the available pattern cylinders give less travel john Quote Link to post Share on other sites
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