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MG MGA - clutch judder question
|Hi folks. I have a problem with my MGA 1500 roadster.|
It seems that I sometimes (but not always) appear to have fairly severe clutch judder. The judder occurs only in first gear, when I release the clutch and the car begins to move forward or in reverse. The judder seems to be worse when in reverse. The judder seems to occur more often when the engine is hot. The judder seems not to happen, or happen less often if the engine is cold. I am assuming this is a clutch problem, but am wondering if it could be something else? Does anyone have any ideas as to what might be causing these symptoms? Thanks, Glenn
|Glen, Whilst this could be a clutch problem there are a couple of other things worth checking before you tear it all apart. Have a look at the engine mountings and see if they are all saggy and soft, if so this is almost certainly the problem. Check the UJ's and also the tightness of the U Bolts. Other than that it seems that you might just have oil on the clutch disc and that you will have to replace it but make sure you sort out any oil leaks when you are in there.|
I get that judder a bit, exactly as you describe. My 1500 has the 1800 engine, 5-speed box and MGB clutch. No oil leaks evident, so it's a good call on engine mounts, especially after Cam's (cunny44?) ditty about vibration. I need to fiddle with the car (the only means of transport in my household at the moment).
|Oh No Steve has sussed my ebay alter ego! Wobbly rubber mounts could cause judder but I would think that weak clutch springs or oil contamination was the culprit ( when the springs heat up do they loose some of their effectiveness - might explain the lack of judder when cold). Mind you - fitting the engine rubber mounts was straight forward but very fiddly & time consuming -and easier than removing the engine. The new rubbers are obviously much stiffer than the original 45 year old(?) ones - slight vibration being transmitted through them - don't know if this is normal when rubber is new.|
|I would be curious as well to find this out. Could a bad pressure plate, such as weak springs cause clutch judder? My pressure plate has been in the car for about 22 years, however has only about 15,000 miles on it.|
Mine also was worse in reverse than forward. I thought it may be oil from the front oil seal on the tranny but that looks good. The front side of the flywheel looks good,(no oil on it from the rear main oil scroll.)
The clutch disc looks slightly dark, but for the most part I can see no oil visible on it.
|I think judder comes mostly from a glazed clutch plate. Kind of like your brakes when you don't use them very hard, they squeal. Add the bit of oil that invariably seeps out of the rear seal, maybe not even enough to drip (and probably soaked up by the clutch lining), and you get a sort of sticky smooth surface. Not good for something that's made to slip, then grip tight.|
The quick fix is to pull the car up to a solid wall or something, pad the front of the car if you must, and slip the clutch. Maybe use second or third gear and set the handbrake. Do this a few times to burn off the glazing, and test. Should improve things for a while.
Why don't they just work flawlessly for 10 years? I guess 'cause they're old British cars, not Hondas or Toyotas. And it's kinda cool that all these quirks bring us together for a social hour or so everyday.
Hope this helps.
I would go with oil contamination also. I give mine a clean every couple of years to stop this.
The application is easy, just buy a brake cleaning fluid in a spray can then get someone to sit in the car with the clutch depressed (or wedge it down). Spray up onto the clutch plate through the drain hole at the bottom of the bell housing. There is usually a straw with the can to direct the flow which makes things a lot easier. Spray liberally and then move the car to get at another section of the clutch. I usually do 4 sections and that seems to work.
I also do try to slip the clutch while driving if the vibration gets bad but have never tried pushing a wall. I am always a bit afraid that too much slipping of the clutch will rapidly wear the carbon bearing on the release fork.
Hope this is useful.
|The clutch shudder in my MGA 1600 was due to the new moulded friction material clutch plate (that I installed during restoration) becoming glazed partly due to my relatively gentle use of the clutch (this material apparently works quite well if you use the clutch harshly!). A replacement clutch plate with woven facings has resulted in the car feeling like an automatic! I think that there is a corollary in the fact that moulded brake linings are nice and "grabby" especially on older cars (such as a couple of Prewar MG's and an Edwardian Rover that I have).|
|I experienced this problem with an old Chevrolet I had when in school.(many years ago.) An old mechanic told me to put the bumper against a tree and slip the clutch until it got warmed up. I hesitated to suggest this method to Glenn, but now that Tom has brought it up I will say that it always solved the problem for me. It was a car that sat outside in the weather and was not driven very often. I always thought it might be moisture collecting in the clutch material as much as oil contamination. What ever it was, warming it up by slipping it for a while always smoothed it right out!|
|While I agree that it is most likely the clutch at fault, but please check the "U" bolts holding the axle to the springs!!!!! And the spring mounting rubber parts. If the "U" bolts are loose or the spring rubbers are warn, you will get an axle "Wrap up" that has all of the symptoms of a bad clutch!|
|I didn't think about moisture, but that may play a part as well. I have a rear brake on the van that grabs if it has rained. Just the high humidity makes it grab, just has to be used hard a couple of times and it goes away.|
I guess you could have a friend check the U-bolts on the rear end while you're trying to push the tree over. I think a concrete barrier may be a better choice though. Spreads the load better.
Slipping the clutch won't cause any more wear on the throwout bearing than regular driving.
Putting the car in 3rd gear with the brakes on should give you plenty of resistance to heat up the clutch plate. You may have to heel and toe to keep the revs up.
I got a kick out of Gene Simmons Family Jewels the other night. He was trying to drive a stick in Europe, saying that there are 3 pedals and he only has 2 feet, etc. In another episode he was trying to buy an island...
I bet the van is a Ford. I have a Ford Ranger and every day we get any moisture on the ground or in the air the rear brakes grab. Makes for a exciting ride when it snows and ice under that in the winter. I can drive with the parking brake on a bit, dry them off and it is good for day.
I never thought to park the car against a shade tree and release the clutch in the higher gears. The engine and tranny are apart now and hope to install a five speed tranny this winter. It comes with a new clutch disc plate, so that will be a factor. From this thread, it seems most folks would agree the pressure plate is good to go back in.
|I experienced that apparent clutch judder from both bad u-joints and loose rear axle u-bolts on my 2nd MGA many rears ago. As for the grabby brakes, I think you would find that they are probably grabby all the time, but you only notice it when the road is slick. In my experience with everything from MGs and Volvos to Chevys and Jeeps, it probably means a leaky rear axle seal resulting in a gooey paste of oil and dust on the shoes and inside the drum. |
|Not just the slick road. The dang thing grabs hard, makes a bang, scares the passengers.|
It's a Plymouth Voyager mini. Probably a bit of grease or brake fluid to make it sticky. I may get around to taking it apart some day. I have had to put 2 wheel bearings in that wheel, probably related to that. Or my lack of mechanical ability.
My latest issue with that one is a balky starter since I drove through flooded streets the other day. I can smack the solenoid and it will start 10 times in a row. Get up the next day, repeat. Sounds like a Lucas fuel pump, eh?
|Tom, A trick used to reduce grabby brakes is to have the leading edge of the Shoes (Pads) chamfered. I would guess at about 45 degrees. This eliminates the edge from being 90 degress and catching the drum and getting pulled into the drum causing the abrupt grab.|
|Thanks, Chuck. I'll have to try that. Tomorrow I have to put the lawn mower back together, though.|
This thread was discussed between 13/08/2007 and 17/08/2007
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