Grease for clutch release throwout bearing?

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Dec 25, 2006
Been using Valvoline Synpower grease for the clutch release throwout bearing and sleeve etc. Just curious if there is something better out there or if this is perfectly adequate? There have been some folks who've had problems with the clutch rlelease bearing failing, heat welding to the shaft/sleeve etc. Haven't had too much experience with the different kinds of grease so I figured this would be the perfect place to inquire. BTW, the car is a modded Mitsubishi 3000GT VR4 running an RPS full carbon faced twin disc race clutch. Been using the Valvoline Synpower for all kinds of greasing, clutch release bearings, tierod ends, tranny output shaft splines (the AWD drivetrain has an output shaft from the tranny that goes into the transfer case to the rear wheels. The splines of the output shaft tend to rust after a while). Any advice or recommendations would be appreciated. Max
Your comments about the release bearing heat welding to the shaft are interesting. Just how high do these temperatures get? Since water washout is not really issue, you should probably focus on the temperature resistance. Maybe something like Mystik JT6 High Temp, which is rated to 325 F, would be better suited.
Bearing races are generally press-fit onto shafts. If a bearing is welding itself onto a shaft, then either it has a foor fit to the shaft or it is a result (not cause) of bearing seizure.
There have been some folks who've had problems with the clutch rlelease bearing failing, heat welding to the shaft/sleeve etc. The splines of the output shaft tend to rust after a while). => Premature wear of the throw-out bearing can occur when there is insufficient clutch play, resulting in a throw-out bearing that spins continuously. If the bearing fails, it may seize and quickly wear the fingers of the pressure plate. given the type of car and the tendency of work being done on the car, I would put my money on the problem being an improper install and setup of the clutch. In this case, no form of lubrication will solve that problem. You must install the clutch, any clutch, properly and make sure everything's aligned and functioning properly. As for grease, lithium complex and aluminum complex greases, and I think polyurea greases, have the highest workable operating temperatures, except for bentone greases which you don't want to use. Check what the valvoliene synpower grease has for a base, or soap type. The soap type is just as important as the oil used in the soap- they may claim its synthetic oil in the grease and you would associate that with being able to function at higher temperatures, but if the soap can't, the grease will fail just the same. My opinion, it's usually the soap or thickener agent that causes the failure by allowing the oil to run out, not reverse back into the grease, or harden, before the oil gets too hot and can't lubricate. Temp wise, a lithium complex grease would probably be best for your application, also the most available and economical. For rust protection on the splines, use aluminum complex grease, it's very tacky and stays put. CRC or Sta-lube puts out a blue grease that's Al-complex, called RV/boat/trailer grease er'something. I use that stuff on everything with splines, it's very good.
checked valv synpower grease product info, it's lithium complex. I don't trust anybody these days who claims synthetic about their oil. But given valvoline's grease lineup, you have their best. Their durablend grease and their GM grease, are also lithium complex greases. Who knows what their oils in them are, or if they're the same. But the other greases are lithium hydroxysterate, which you don't want if you want maximum temp capability... so look for "lithium complex" when choosing a grease for that reason.
Thanks for the info. BTW, the clutch release (TOB) bearing is a closed assembly that slides on the shaft and applies pressure to the clutch pressure plate via the clutch fork when the clutch pedal is depressed. The folks who had the TOB heat weld itself to the shaft had problems with the grease that was applied to the shaft. The TOB wasn't gliding properly on the shaft and ended up marring the shaft and this caused the TOB to catch and eventually seize. The friction then burnt the TOB and that was when the heat welding occurred. Well, from the looks of it, I guess I should be OK with the Valvoline Synpower. Max
Does anyone know how a moly grease would work in this application? For example, Valvoline DuraBlend which is rated to 400F.
Seems to me that this is a perfect application for a grease like MolyKote G-407 that has moly and a synthetic oil base. If it gets hot enough, the synthetic carrier oil evaporates leaving a dry-film coating of molybdenum. Or at least this is what the G-407 data sheet says. It's hard to find G-407 in small quantities though. But I'd bet any of the quality moly-containing synthetic greases by Amsoil or Schaeffer's would work fine. I believe you can find the same type of protection in some of the high-end disc brake caliper greases. I can't remember the name, but one of them had similar action to the MolyKote G-407 - when the carrier evaporated under high heat, a dry-film lube remained... Just my few thoughts. later, b
Honda makes a grease specific for this application. It is a UREA grease and can be found at most dealerships. PN 08798-9002 and is actually a made in USA product. I've never experienced a problem with this grease, been using it for about 8yrs now. Smoky
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