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Triumph TR6 - 'Frozen' transmission on '74 TR6
|This happened all of a sudden; no recent shifting problems. Over the course of one day it was increasingly hard to shift into first gear. Once in first, after a good bit of coaxing, it went up through the other gears with no problem. Down shifting into third and second were only somewhat difficult(still not just right.) But after a full stop, it was almost impossible to get into any gear.|
Well, now it's home, parked in my garage, and with the engine running it will simply not shift at all. Interestingly enough, when the ignition is off I can shift through all gears with no difficulty at all. I can drive by putting the car in first (clutch in) before starting it. But there is no guarantee I will get through the other gears, and for sure not back into first.
So, any ideas? Clutch? Tranny? Fluids? Murphy?
Thanks for any help,
|sounds like the clutch fork tapered pin has partially sheared and thus will not disengage making it very hard to shift when the engine is running. When the engine is off then it is easy to run through the gears. Your discription sounds like a classic sheared pin symptoms|
If this is the case the part is cheap $10 but the repair is time consuming as the transmission has to be pulled and the pin replaced.
|Thank you Steven.|
Can't do a job like this myself. At $50 to $75 USD for professional help, any experience on how long a job like this could take?
|Keith - A good shop with TR experience should take 5 to 6 hours to remove the seats, unbolt the gearbox cover, unbolt the drive shaft, remove the starter, block up the oil pan, unbolt the bellhousing plus rear g/box mount - and with the help of another person for a few minutes - pull the gearbox. To remove the sheared tapered pin you may have to drill a 1/4" hole in the bottom of the aluminium bellhousing to have straight-line access to drill out the remaining part of the broken pin. Then later, you can tap this hole and put in a flush bolt if you want to close up the hole.|
Go back to the main screen for TR6 on this BBS and click about 6 or 8 titles lower down entitled "tr6 clutch pedal hard". There is a lot of info there - especially the tech article on heavy clutches by the Minnesota Club.
If it is the tapered pin that has sheared, ask about drilling through and inserting a hardened steel 1/8" press-fit "C" pin right through the yoke and shaft to secure it to the cross-shaft. I put in a Grade 8 bolt (1/4" - 20 UNF) bolt and nyloc nut to eliminate the problem of a broken tapered pin ever again. The pin is easier to do.
Why don't you buy the manual for your TR6 and check out the diagrams in the parts catalogs from Moss, Roadster Factory etc. and do the job yourself. You will leard a lot and with the help of this BBS and others, you can save a lot of money.
Check out the VTR members in your area if you are not a VTR member yet. They have a chat-page. Send in the same question to MNTriumph@yahoogroups.com
Good luck and please come back and tell all of us other TR owners what the real problem was.
Don Elliott, Original Owner, 1958 TR3A
There is a pretty simple way of determining if your problem is hydraulic or mechanical ie. the taper pin.
Go to the TRIUMPH TR6 WEB
go to PROCEDURES/MECHANICALS/HYDRAULIC CLUTCH BASICS.
If you find out it is a hydraulic problem then you can fix it yourself. I agree with Don, let us try to do our own repairs and learn and have fun at the same time.
I am not totally convinced it is the taper pin. I do not have experience with sheared taper pins and will gladly stand corrected if I am wrong. If it is sheared then you would not have a clutch at all and you would be in gear as you started the car ( There is a obvious warning here). No offence Steve but I do not know how you could have a partially sheared pin. I do not know if you could even have a bent pin. I have seen with my car when putting her back together that the taper pin hole was rounded allowing play in the pin to shaft tightness (this would not happen over night). I ended up replacing all before reasembly. I do regret that I did not put in the extra bolt as Don has explained. I was told the new pin was far better than the OE pin. For your sake Keith, I hope it is hydraulic and not the pin.
See if you have that 1"to 1.5" "throw" in the clutch shaft arm. By all means keep us informed as to the correction.
|Thank you everyone for all of the help.|
I'll check hydraulics next, and hope beyond hope that that is the problem. It would certainly be easier, a sure do-it-myself, and certainly cheaper.
I know it may sound strange about a partially sheared pin. I was having problems shifting when I put in a used transmision (I bought an O/D 0as the cluch did not fully release. I put the transmission in with out fully checking the pin as I was originally concerned on on the status of the O/D unit and wanted to test it before putting all the interior stuff back in.
When I pulled it, the taper pin came out in two pieces however the friction around the fork and the broken parts of the pin still held it together but at a different attitude allowing partial release of the clutch. If it was a clean shear then the clutch pedal would go to the floor with no resistance and may slowly return to the original position with the internal springs in the hydraulic cylinders.
Keith: Taking out the transmission is not that difficult, lots of unbolting and just time consuming. Just make sure that the rear of the engine is supported when you separate the two. The manuals explain the process very well . The job just takes longer than other cars because you have to remove the interior including the center consol bracket and radio etc. It you are not inclined to pull it yourself you still can save a couple hours of labour cost by removing the all interior parts including the transmission tunnel cover. once removed you can drive the car over to the shop just make sure there are no loose clothing or other objects near the spinning drive shaft .
Perhaps first though is to check the hydralics making sure there is no leaks or air in the system, perhaps blead it and make sure the throw lever connected to the slave is in the middle hole
|Steven and Keith|
I STAND CORRECTED! and have learned something from another TR owner. Hay..isn't this one of the reasons for this BBS? We all want to hear your results Keith.
Steven from Toronto is right. That is exactly what happened to me. Although it is a hassle, do the job yourself. Lot of self satisfaction. If the pin is the problem, you may find that no matter how hard you try, you can not get the end piece out while it is still in the bell housing. Do not fret, just cut the shaft (buy a new or used one) and put the fork on a vice and work it off the shaft. I just did this job last month (my second time doing it), if you want more advice, e-mail me, I can walk you through it. Also, the added pin that Don talks about is a must.
|if it is the pin just drill a hole in the other side of the clutch fork & knock the broken piece out with a hammer & punch, i've found this to be the cheapest & quickest.|
|Keith, I just went through almost exactly what you were describing and it was simply that my clutch master had gone dry ( thanks to a leaky slave cylinder ).|
With luck it may be something that simple.
Ordered new seals for the master (so that's what the black stuff on my shoe is) hoping that it's that simple. But I have a quick quiz question before I begin the project.
Step number one is to drain the system, right?
So, will I be able to pump fluid all the way out through the slave bleed nipple if the seals in the master aren't allowing enough pressure to operate the slave?
Right now this is all in my head; I haven't actually "gone in" yet.
|Keith - all you have to do is loosen (or completely remove) the bleed valve on the slave cylinder down under the car near the bellhousing. Be sure to use solid jack stands after you jack up the car and shake the car back and forth to make sure it is all solid before going under.|
You will want to check the actuation of the rod at the clutch slave cylinder before you start - to see what you have in the way of fluid pressure. Have a friend or "significant other" pump on the clutch pedal (MAKE SURE THAT PERSON KNOWS WHICH IS THE CLUTCH - AND NOT THE BRAKE PEDAL)to build up pressure while you watch under the car. If the rod doesn't move, you have no clutch pressure needing new seals and/or fluid.
Open the bleed valve on the slave cylinder. If, for some reason the fluid doesn't come out, it may be that it is already empty. Check the reservoir for the master cylinder for the clutch. If it is empty, you'll need to change the seals in the clutch slave cylinder too. Not a bad idea when you think about it. Better now when it's all apart than later (like next summer on the road). It's always wise to do a complete job, not just a bit at a time. If it still won't drain out, remove the pipe fittings on the master cylinder and the fluid will drain down as air enters the top end of the clutch feed line.
When putting it all together again, you will need to "bench bleed" the master cylinder. If you take out the master cylinder, and have it on the bench, fill the reservoir with new brake fluid, get all the air out that part, put plastic plugs into the outlets, then re-install the master cylinder in the car. This "bench bleeding" can also be done if you leave the master cylinder in the car, providing you slack off the fittings at the outlet. Fill the reservoir and the open fittings allow the fluid to flow down to that fitting, expelling the air as it flows. Close the bleed valve on the slave cylinder and re-connect the tubing from the master cylinder feeding down to the clutch slave cylinder. By doing this "bench bleeding", the reservoir has no air left in it and you will only need to bleed the feed line. Check that the reservoir is full. Open the bleed valve on the slave cylinder and the fluid should come down by gravity. If you have to bleed the air out, do it in the conventional way. Have your friend pump on the clutch pedal to build up pressure. While still pushing down hard on the pedal, you go under and open the bleed valve to let out the air. Close the valve. Then the friend can take ghis foot off the pedal. Then he pumps again and you repeat this till there is no air left in the line. This will be when no more air bubbles are spitting out and when you can see that the rod from the clutch slave cylinder is moving out about an inch as it should.
Make sure to add fluid to the reservoir after each pumping/bleeding operation because if it gets low in the reservoir, air will get into the master cylinder again and you'll have to start this "bleeding" all over again.
Find out if you can whether your TR6 uses regular high quality brake fluid or silicone fluid. Whichever it is, stay with that. Don't switch or mix different brake fluids. If it has been using regular fluid and you switch to silicone you will have to change the rubber hose at the bottom too - if you don't, the rubber will go gummy and be ruined. If switching to silicone fluid, you will have to change all the rubber for new rubber (seals, hoses etc.). If you only change it for the clutch, you'll forget which (clutch or brakes) still has the other type.
Let us know what you find.
Don Elliott, Original Owner, 1958 TR3A
Does your clutch shaft arm have the 1 to 1.5" travel??? This is a big question which can be answered it less than a minute. Other guys think it is mechanical and they could be correct. I "hear" you say the point of the black stuff on your shoes so I continue with the thought that it is a hydraulic problem. Don has the procedure. Let me add my 2 cents here. Don said do not mix DOT4 with DOT5 brake fluid. This is VERY true. DOT5 is the synthetic one and if your system had .4 in it and .5 was accidentally added later to "top up" then all your rubber seals would turn to gum and you would have black stuff dripping on your shoes. I do not think this happened though. It could also be that your rubber parts in the cylinders have "just deteriorated" and dripping on your feet. If it has happened to the master then the slave also has the same problem. There is also the posibility of the bore walls of the master (and maybe slave) are pitted and fluid is leaking past the seals. I remember reading an article on the red flex hose that connects the solid pipe to the slave. The person stated that his flex hose was old (original) ..OK you can start laughing now..and that as the pressure from the master cylinder pushed brake fluid through it, it expanded resulting in the pressure not going to the slave resulting in less movement of the clutch shaft resulting in..... I mention all this because there is a fast and not to expensive solution. Victoria British offers a complete kit (PN CRK500). Other suppliers may offer it also. The only thing not replaced is the metal line. NOTE: Victoria British says not available but MOSS has the line. The kit is around $150.00, under $200 with the metal line, and you know that everything is new!! One final thought. If you go the route of the kit then I would suggest you go to DOT5. It is MORE expensive but has 2 big advantages. Does NOT destroy a paint job and does not absorb moisture. I would remove the metal line and let it drain for a while then flush it with .5(or replace). YES you will have to remember that your clutch is DOT5 but then you should not be having to top it up in the first place. I am .5 both clutch and brake system (both systems completely new). I like the idea of not absorbing moisture as my 6 sits for 6 months of the year. Have fun and let us know what the travel of the arm is (if any).
|Rick - I have used silicone brake fluid since 1990 when I finished my restoration. I too changed all the seals and hoses. I have never had any problems till this August. While silicone fluid will not absorb humidity, I found out something new that I thought I'd share with all of you. Montreal is at 37 feet above sea level. I never felt that I had any air bubbles in my clutch or brake lines.|
In August, I drove my TR3A to VTR in Colorado. In Loveland, (Altitude 5000 feet) I turned each SU carb leaner by one-half a turn to account for the reduced oxygen in the mountains. In two hours, I had climbed to the top of Estes Pass in the Rockies (Altitude 12090 feet). The carbs ran fine but I had to pump on the brakes and the clutch pedal at least twice before feeling any pressure.
I can only conclude that, like a deep-sea diver that come up too fast and gets the "Bends" - Nitrogen coming out of solution in his blood lines, the air bubbles that were tiny at Sea Level, became a major factor in my clutch and brake lines at 12,090 feet. With the help of a friend, Bob Palmer from Akron, Ohio, we bled all the lines and it was fine after that. A lot of air was spitting out and we had to do each coener at least 5 or 6 times to get rid of the air.
You think you know all the gremlins in your TR till a new one attacks you when you least expect it. Get to know the gremlins in yours and listen to the noises they make before they pop out at you, in the middle of the desert in the middle of the night. Make them your friends and they won't surprise you.
Don Elliott, Original Owner, 1958 TR3A
|If you are rebuilding your master and slave STAY AWAY FROM 'PBR' seal kits. They are made in Australia and are crap, poor quality control and do not function properly. Use Lusas seal kits. If there is any pitting or scoring inside the cyclinder then only solution is to buy a new unit. They can be resleeved but the cost differential is not enough to make it worth it. Buy new. Usual culprit is the slave as this is cast iron tand ends to rust inside. |
I would say buy a new slave then rebuild it as last time I looked in to it the cost differential between the seal kit and the complete new slave was $25
Also if rebulding the master make sure you buy the right size, there were 2 sizes being used .70 and .75. I believe that it is stamped on the side of the cylinder
Interesting story. I would probably not even thought about the altitude thing and would have thought I had problem with the carbs (and brakes). It would be interesting to know if DOT4 would have done exactly the same thing????
I am very satisfied with .5 and am glad FRED suggested it at begining of the restore.
Maybe we should all go to Colorado to bleed our brakes:)
This thread was discussed between 06/11/2001 and 19/11/2001
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