QuestionHi:
I recently had my car serviced by a top notch MG shop. The mechanic said he felt something in the gears and bled the master cylinder and adjusted things but felt it just wasn't right. Having only ever driven my MGB it seemed normal to me that sometimes second took a little time to open. Now when I come off a dead stop the car bucks and grinds and sometimes won't go into second. Is this the early signs of a worn clutch? The car (1977) has 72K miles on it and I don't know if the clutch was ever replaced. Are there any tests I could do? Any way to determine what the problem is? I understand replacing the clutch is a big job requiring an engine pull and is very expensive $800+. I only paid $4,000 for the car dropping 1/4 of its price for a new clutch hurts.
Thanks,
Hugh
AnswerHi Hugh,
To give the clutch a rough test as we use to do in the dealerships. First push the clutch pedal in with your hand. It should move not more then an inch free play and then the pedal should be hard to push and if you push it all the way to the floor it should feel about the same resistance all the way. If it is easy to push at first and slowly gets harder to push as the pedal goes down you may have a hydraulic problem. (most likely air in the system)
If it was hard to push just after the first free play the hydraulic system is most likely ok.
Next test is to start the engine and let it warm up and be sure the idle is 800 RPM or lower.
Push the clutch all the way to the floor and wait for 5 to 10 seconds and put the car into reverse.
Did you get any gear clash? If so, continue to hold the pedal down and be sure you have released the hand brake and foot brake and on level ground and note if the car tries to creep.
If you get no gear clash and it does not try to creep it has passed that test.
Next test is to take it out on a straight road that you can get up to cruise speed in fourth gear and hold the throttle steady and don't move it and quickly stab the clutch pedal down and up. The engine RPM will momentarily go up but as the release of the quick stab of the pedal will result in a jerk forward of the car. You must do it quick so the RPM don't go too high and you must not let off or on the throttle. If you get a jerk forward the clutch has passed that holding test and does not slip. If the quick release of the clutch gave you a smooth acceleration rather then a jerk then you have a slipping clutch.
The reason it must be done in 4th gear is that is where the most strain is on a clutch. And the reason you do it at a good cruise is that you want to see about 3500 RPM because that is the engine's most torque.
If it passed all of these tests and it grinds going into 2nd gear it is not the clutch it is the syncro rings on 2nd gear in the gearbox is worn. Yes, it can only be replaced by removing the engine. There is however a possible temp thing you can try. BLM said to use gear oil in the gearbox but we learned very early in the life of MGs that if you drain that out and use engine oil instead you will get a longer life out of the syncros.
A syncro is a small cone shaped clutch in-between the gear and a sliding hub assembly that must get both spinning at the same speed to engage each other to lock into that gear and the thick gear oil will not allow that clutch to hold. The thinner oil will allow the cone to squeeze out the oil and allow the cone to grab and get both spinning at the same speed.
If when the clutch is out and you are accelerating and getting a grinding noise in the gearbox, that may be either badly worn gears or a bad bearing.
You need to read my tech tip on how to make a gearbox live longer. Go to,
http://mg-tri-jag.net/tech4.htm
Howard
