|The MGA With An Attitude
Cleaning an OILY CLUTCH - CT-105
At 02:47 PM 5/1/05 -0600, Dan Garfias wrote:
"I rebuilt a leaky master cylinder and replaced the slave cylinder and flex hose. I am now dealing with a slipping clutch. I came across an aerosol can of Trichloroethane, sold as 'Brake cleaner' for brake drums, discs, brake linings, and clutch assemblies."
The good news is, if you have oil on the clutch, this stuff can possibly clean it off. The bad news is, if you have oil on the clutch and you clean it off, it will return with time. You will ultimately need to fix the problem causing the oil deposition. Otherwise you will be forever repeating the cleaning procedure.
This is really good solvent. Spray it on, watch the oil run off in a flash, and allow it dry (usually in a minute or less). Great for brakes and clutch linings. It is also extremely harsh on human skin eyes. Spray it on your fingers and it will instantly remove all oil so you won't leave finger prints for a few hours. The dried skin wears off after a few days. Spray it in your eyes and you will be instantly blinded (with considerable discomfort). Immediate prolonged rinse with cold water should restore your vision in about 20 minutes, but your itchy eyes will be bloodshot for a week. Wear full coverage goggles when using this stuff.
About 25 years ago there was a big move to remove this product from the environment. Many commercial brake cleaner products switch to more benign chemicals, most of which also do not work as well. Some of the major brand brake cleaners now seem to run off like water and do almost nothing. Luckily the trichlore chemicals were not specifically banned by name, and the base chemicals are cheaper than most of the substitutes. So in spite of some environmental difficulties in manufacture, this stuff still survives today. It is actually most common in the lesser known off brands of brake cleaner which one might think could be inferior to the major brands, but turn out to be much better.
"The can had a length of small diameter plastic tubing, pushed into the nozzle. 'A powerful blend of cleaning solvents' it said "
No kidding. It will "clean your clock" right quick. if you get it in your eyes, nose or mouth.
"If you take off the circular plate from the top of the bell-housing, the rear of the clutch assembly is revealed."
Not for MGA, MGB, or Midget. Maybe for the front drive MG 1100 or Austin America, Mini Cooper, etc. For the MGA you might remove the starter motor and reach in around the edge of the flywheel / ring gear. You can remove the lower bolt for the clutch slave cylinder to gain access to spray solvent inside the bellhousing, but this hole is 2-1/2-inches aft of the bolt flange, or a full inch aft of the interface point between friction disc and flywheel. At this location you would be spraying solvent on the outside of the clutch cover where the solvent may not reach the desired location on the friction disc.
"If you nudge the engine round, a circular hole about 1-1/4 inch diameter comes into view. This gives access to the back of the clutch pressure plate which doesn't help very much, so I drilled a 1/4 inch diameter hole above the larger hole, as close up as possible to the flange that is bolted to the back of the flywheel. This gives access to the edge of the friction plate."
Where the pressure plate bolts onto the flywheel, the area immediately around the six bolts will be in intimate contact with the flywheel. For the rest of the periphery of the pressure plate the flange is relieved slightly away from the face of the flywheel. The space here is just about large enough to accept the tip end of the little plastic tube which comes with the spray can of brake or carburetor cleaner. If not then bend the tub to point in this direction, place the tip of the tube up to the narrow slot, and spray the cleaner into the slot. This will put the juice into the space between the flywheel and friction disk. Spray it generously, and with luck some of it should spill over to the back side of the disk next to the pressure foot.
Have a helper depress the clutch pedal to pull back the pressure plate. Spray the cleaner to enter between the friction disk and the adjoining steel plates (flywheel and pressure plate). Lift pedal to engage clutch so the disk will turn with the assembly. Rotate flywheel 1/3 turn. Repeat press and spray in three places around the sides of the clutch. Hold pedal down for a minute or two to allow draining and drying time.
"A piece of small bore plastic tubing pushed over the tube supplied with the can and inserted through the 1/4 inch hole directs the degreaser right into the heart of the clutch - having first pushed the clutch pedal down. Give four or five hearty squirts of the aerosol and leave it to dry off. It is very quick. I found that it was wonderfully effective and am now able to drive without the dreaded slip. Highly recommended!! I shall not have to strip my engine after all. I will write again as my experience increases."
I have used the same cleaner to remove oil from electrical assemblies, such as cleaning the brush gear in a generator. It is truly a miracle solvent, as long as you don't damage yourself while using it. It will also dissolve rubber parts and the glue from electrical tape, but cloth and PVC wire insulation should hold up okay to brief exposure. Early MGA cars used rubber insulation in the wiring harness with color codes in braided cloth coverings on the wires, braided cloth harness covering, and rubber covers on the female bullet connectors. Later cars and all modern replacement parts use PVC insulation on individual wires with color in the PVC, either cloth or non-adhesive tape wrap over the harness, and PVC covers on the female bullet connectors. Phenolic insulators are impervious to the solvent. Nylon insulators should hold up okay to brief exposure, but nylon parts commonly get brittle with old age regardless.
Good luck with your clutch, and let me know if a good cleaning helps (and if it holds up with continued driving). A worn out clutch disk will slip even when it is clean, and the only cure is to R&R the engine to replace the clutch disk.