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MG MGA - Clutch? Gearbox?
|Been having problems with my 1978 1500 midget. A few months ago I couldn't get reverse gear whilst the engine was running, and with a struggle just about able to get first. After flushing the hydraulics it seemed to fix it for a while, however yesterday whilst driving around Abingdon, I tried to change down through the gears, only to feel the clutch pedal tighten and unable to get any gears at all. Using the revs I managed to get it into second gear and pull into a layby. Weird thing is, when the engine is off, the gear change is fine, turn it on and nothing, stuck hard. I can just about move it side to side. Anybody else had this happen to them? Does it need a new clutch? I'm not an expert on the mechanical side. It's my first MG and i'm still learning the basics.
|It would be best to ask this question on the Sprite/Midget board rather than the MGA board. However, what you describe sounds like a classic problem with the clutch or clutch hydraulic system. If you can recruit an assistant, put the car up on jack stands, crawl under it, have an assistant depress the clutch pedal and measure the distance the throw out bearing fork moves. My measurements, of properly running MGBs, shows a movement of about 3/8". Others have claimed movement of 1/2", but I do not know what they were using for a measuring device. If you have the 3/8" of movement, the hydraulic system would seem to be working properly and have sufficient force to move the throwout bearing against the pressure plate and depress the pressure plate, allowing the clutch plate (driven plate) to move out of contact with the flywheel. If you do not have this length of movement, the seals in either/both the master cylinder and/or the slave cylinder are leaking and the system needs to be rebuilt before further testing can take place.|
|My apologies. I thought I had posted on the Midget board. Is there anyway, I can port it over there? Thanks for the advice about the clutch. I'll put it on the ramps tomorrow and take a look. Is it worth just replacing the whole clutch unit to fix this problem rather than tinkering with it?|
|Do not know if it is possible to transfer a post from one subunit to another or not. But, you should get some responses here--they are similar systems. |
I do not know what you mean by "the whole clutch unit". The clutch system consists of the master cylinder (in some cases, a joint brake/clutch system having two bores in the same unit), the slave cylinder, the lines associated with them, both hard and rubber, the throwout bearing, the pressure plate (clutch plate), and the clutch (driven plate). Associated parts are the pilot bushing (spigot bushing) and the flywheel. Replacing the clutch assembly normally requires that, at least, the engine be removed.
Hence, I would suggest a through check out of the clutch hydraulic system as a first step. If that cures the problem, you are good to go. If not, it is something you would want to do anyway when doing a clutch assembly replacement on a car that has an unknown repair history. Unless you know that the clutch hydraulics have been recently rebuilt, they are the first place to start an investigation.
|One of our club members had problems with his Midget clutch last year - he had it out 3 times before he found the problem. One of the linkages had a slightly oval hole and this together with other wear in the linkages resulted in the clutch piston not moving far enough. Good luck and have fun - I started with Midgets too, moving up to my MGA via an MGBGT.|
|I had a lot of trouble similar to this in my MGA when I first got it running. Hard to shift while driving, got worse after the engine/trans had warmed up, but fine with the car off. Frustrating.|
At the suggestion of another poster, I checked my oil level, and though I thought it was OK - it actually accepted almost another quart of oil, which seemed to help immensely. The dipstick is very hard to get at and hard to read.
I also had a @#$% of a time bleeding the clutch. I finally changed out the clevis pin on the fork arm for the slave, which was very worn, and bled the system from the bottom by disconnecting, compressing the slave cylinder with a clamp, and then filling from the bottom through the slave cylinder bleed screw with a syringe.
I am not familiar with how similar or different your Midget's setup might be, but I now have a working clutch!
JIM in NH
This thread was discussed between 30/08/2011 and 31/08/2011
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