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MG TD TF 1500 - clutch engagement
|I rebuilt my transmission a year ago and since then I am having trouble getting the clutch to disengage completely.It has the required half inch of play at the pedal. When in gear and the pedal is fully depressed the car slowly idles forward. Otherwise the gears shift ok except for 3rd which requires a fairly long pause or it will grind. I tried shortening the clutch shaft but it didn't change much. I was wondering can the carbon throw out bearing hang up on the tranmission input shaft?|
First read this website, if you haven't already,
Unless the bushings in the bell housing are completely worn, I can't see the carbon block snagging the input shaft of the gearbox.
First examine the bellcrank on the side of the engine sump. When you operate the clutch, the belcrank should swing in an even arc, and the belcrank on the bell housing should swing in a similar arc. If they don't, you have too much play in the different contacts points of the rods and fulcrum levers (bellcranks). You should fix the play, welding up the holes and redrilling them the correct size. The mods described by the website above are entirely worthwhile, although with proper tight links, you don't usually need the rod extension mod (the rod is the right length already unless the freeplay in the system renders it 'short').
Once you've made your repairs to your linkages, and readjusted your clutch pedal free play by adjusting the threaded rod at the engine sump, you should be good to go. If not, you may have to pull the clutch to inspect it.
It isn't unusual for third gear to require a pause, and with a poorly operating clutch, it may even be more likely. Don't hold the clutch in while you have this problem (or even after you solve it) use neutral to save the wear of the carbon block.
You may wish to visit my photosite, http://www.dbraun99.com/mgtd15470/ and look at the gearbox and clutch section.
|N; Most likely problem is from issues Dave describes-might try temporarily eliminating all free travel in clutch to see if symptom changes. Do not use the car in this configuration - strictly for test purposes. One other cause of creep we have seen occur is damage to the pilot or spigot bushing-keeps the input shaft turning even with clutch plate released. A bit out of the ordinary, but have been beat up by it a couple of times over the years. Most likely linkage,bellcrank and/or bushing issues-and they are way easier to repair. Hang in there, Dan|
|I had a similar situation after I first installed the engine and gearbox in Lazarus. It turned out that the culprit was an undersized spigot bushing in the flywheel.|
I still have the guilty party sitting on top of my desk.
|Thanks guys. I am concerned about the pilot bearing as it seems to vary with engine temperature. I sure don't look forward to pulling the transmission again. Do you have any secrets to replacing the bell housing bolts. The one at 7 o'clock with the ground wire is almost impossible to reach.|
|See O'Conner Classic treatment. It will fix your problem. I've been there|
|Sounds like a case of a flywheel having been skimmed on it's working or clutch face, which means everything moves forward slightly, except the carbon thrust bearing, which then does not fully disengage the clutch. Better to never ever skim this face even if it has scratches; a light polishing with fine emery will suffice.|
|R A WILSON|
|Could also be the result of using a 7.25" clutch in an 8" engine/transmission unit, but this would mean changing the flywheel to the early type.|
|R A WILSON|
|Try using a 1275 midget throwout bearing (Moss p/n 190-920). This was recently discussed on the T-ABC website so I tried one in my TC transmission (we use the same throwout bearing as the TD transmission). The Midget throwout bearing has a larger offset and a thicker carbon ring and should easily engage the clutch.|
In my transmission it transformed the feel of the clutch, making it much easier to shift.
This thread was discussed between 19/03/2009 and 27/03/2009
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