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Lube for poly bushings ??
- Thread starter ALLAN
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crj7driver
Jedi Trainee
Offline
I would love to know this as well, as hopefully I will need to lube up my bushings very soon. I think when my mechanic installed them he just used regular grease, but after 5-6 years they started squawking.
Alan_Myers
Luke Skywalker
Offline
Hi,
First of all, just applying grease when assembling standard smooth bore polyurethane bushings will usually only give brief lubrication to the joint. The grease will only be a thin smear in there and will likely be squeezed out and/or washed away pretty quickly and there will no longer be any lubrication or corrosion protection in there. Ideally, buy ready made *greasable* urethane bushings if you can. These are becoming more and more common as manufacturers are trying to address the squeeking issue and also recognizing that suspension joints working more freely, i.e. without "stick-tion", are a good thing! I think the most likely type of urethane bushings to find in the greasable type *with zerks* are "universal" sway bar body/frame mounts, but there are other types (see below).
If the greasable type aren't available for a particular application, it's possible to drill the bushing, and whatever it fits into, to install a zerk. Just drill as small a hole as possible for a zerk and be careful about location so as to minimize weakening the part... control arm ends, for example. Zerks can be bought with various size threaded ends. I'd choose the smallest possible in most cases.
Once the zerk is fitted and the hole is drilled through the bushing, a channel to distribute the grease still needs to be "carved" inside the bushing's bore. A Dremel tool with various cutting tips, or similar, on a low speed can be used to carefully do this.
One school of thought is to use plain white lithium grease in urethane bushings. It's easy to find and all that will be needed is a dedicated grease gun, if zerks are installed. White lithium grease seems to work and not damage the urethane, but might tend to wash out pretty easily, so may need to be applied more often. White lithium also comes in spray cans, but I'd be a little concerned about the effects of the carrier that's used to spray it (which evaporates) and its effect on urethane.
Prothane (www.prothane.com) is a major U.S. manufacturer of urethane bushings. They offer their own Supergrease especially for use in urethane bushings. They do supply some greasable urethane fittings with zerk fittings (such as roll bar body/frame mounts) but have also taken a different tack with other bushings (i.e., control arms) molding grease retaining ridges inside the bushings but *not* drilling for zerks. The idea with these is that if their Supergrease is trapped in there, the bushings will seldom (if ever) need attention. Dunno how well this works, but it does help avoid weakening the control arm with a drilling for a zerk. I haven't found a local or online supplier for Prothane Supergrease, so haven't used it yet.
Superflex (https://www.superflex.chriswitor.co.uk/) is a British urethane bushing manufacturer (often with a nice selection of shore/durometer or different hardness bushings for some cars). This company doesn't seem to have started offering greasable designs yet, or special grease. But, they do include "assembly lubricant" for some types of bushings, and they sell this lubricant itself separately in little squeeze packets.
I guess the thinking behind using synthetic grease on synthetic bushings is that the two will be compatible. I honestly don't know if that will always be the case. I have used a synthetic chassis lubricant (Mobil 1) on urethane bushings with no apparent problems. However, I'm not at all certain that all synthetic greases will be harmless to urethane.
Also note that Mobil 1 may not be 100% synthetic. It says right on the packaging that "carrier oil" used in it might be mineral based (which could soften or damage urethane over an extended period of time, although I've not seen any problems in 5 or 6 years using it).
Another lighter grease I've used a lot (but not in urethane bushings yet) is Finish Line Synthetic Bicycle Grease with Teflon. Besides being the best smelling grease I've ever used, it is also white and seems harmless to plastic and urethane. Besides bicycle bearings it's intended for, I use it in camera lenses, where the fact that it never "oils off" like so many grease do is an important property. It also doesn't thin or thicken with temperature extremes. Many camera mechanisms have white nylon (Nylatron) in them and this grease seems to do no harm to it, so might be useful in urethane bushings, too. It is a bit lighter than Mobil 1 chassis grease, but both are stated to be waterproof.
By the way, most folks buy urethane bushings in a "kit" that's supposedly designed for their particular car. In fact, many of the bushings on Triumphs are "universal" type that can be bought by size, or at least close enough to trim to fit. Urethane can be machined, shaped or trimmed in various ways, generally with a low speed, sharp cutter to avoid friction and melting. So, if a particular "kit" doesn't appear to be available, or you want a softer or harder bushing than you see in kit form, or you just don't like the fit of a particular bushing in a kit, it's possible to order them by size or close to size and then trim to fit. (This isn't possible or is more difficult with some cars, such as Land Rover which use a number of really huge bushings in their suspensioni, most of which really need to be specially made). There are even blank "rods" of urethane material available to work with. Superflex (for one) sells these in four different hardnesses.
Hope this helps!
First of all, just applying grease when assembling standard smooth bore polyurethane bushings will usually only give brief lubrication to the joint. The grease will only be a thin smear in there and will likely be squeezed out and/or washed away pretty quickly and there will no longer be any lubrication or corrosion protection in there. Ideally, buy ready made *greasable* urethane bushings if you can. These are becoming more and more common as manufacturers are trying to address the squeeking issue and also recognizing that suspension joints working more freely, i.e. without "stick-tion", are a good thing! I think the most likely type of urethane bushings to find in the greasable type *with zerks* are "universal" sway bar body/frame mounts, but there are other types (see below).
If the greasable type aren't available for a particular application, it's possible to drill the bushing, and whatever it fits into, to install a zerk. Just drill as small a hole as possible for a zerk and be careful about location so as to minimize weakening the part... control arm ends, for example. Zerks can be bought with various size threaded ends. I'd choose the smallest possible in most cases.
Once the zerk is fitted and the hole is drilled through the bushing, a channel to distribute the grease still needs to be "carved" inside the bushing's bore. A Dremel tool with various cutting tips, or similar, on a low speed can be used to carefully do this.
One school of thought is to use plain white lithium grease in urethane bushings. It's easy to find and all that will be needed is a dedicated grease gun, if zerks are installed. White lithium grease seems to work and not damage the urethane, but might tend to wash out pretty easily, so may need to be applied more often. White lithium also comes in spray cans, but I'd be a little concerned about the effects of the carrier that's used to spray it (which evaporates) and its effect on urethane.
Prothane (www.prothane.com) is a major U.S. manufacturer of urethane bushings. They offer their own Supergrease especially for use in urethane bushings. They do supply some greasable urethane fittings with zerk fittings (such as roll bar body/frame mounts) but have also taken a different tack with other bushings (i.e., control arms) molding grease retaining ridges inside the bushings but *not* drilling for zerks. The idea with these is that if their Supergrease is trapped in there, the bushings will seldom (if ever) need attention. Dunno how well this works, but it does help avoid weakening the control arm with a drilling for a zerk. I haven't found a local or online supplier for Prothane Supergrease, so haven't used it yet.
Superflex (https://www.superflex.chriswitor.co.uk/) is a British urethane bushing manufacturer (often with a nice selection of shore/durometer or different hardness bushings for some cars). This company doesn't seem to have started offering greasable designs yet, or special grease. But, they do include "assembly lubricant" for some types of bushings, and they sell this lubricant itself separately in little squeeze packets.
I guess the thinking behind using synthetic grease on synthetic bushings is that the two will be compatible. I honestly don't know if that will always be the case. I have used a synthetic chassis lubricant (Mobil 1) on urethane bushings with no apparent problems. However, I'm not at all certain that all synthetic greases will be harmless to urethane.
Also note that Mobil 1 may not be 100% synthetic. It says right on the packaging that "carrier oil" used in it might be mineral based (which could soften or damage urethane over an extended period of time, although I've not seen any problems in 5 or 6 years using it).
Another lighter grease I've used a lot (but not in urethane bushings yet) is Finish Line Synthetic Bicycle Grease with Teflon. Besides being the best smelling grease I've ever used, it is also white and seems harmless to plastic and urethane. Besides bicycle bearings it's intended for, I use it in camera lenses, where the fact that it never "oils off" like so many grease do is an important property. It also doesn't thin or thicken with temperature extremes. Many camera mechanisms have white nylon (Nylatron) in them and this grease seems to do no harm to it, so might be useful in urethane bushings, too. It is a bit lighter than Mobil 1 chassis grease, but both are stated to be waterproof.
By the way, most folks buy urethane bushings in a "kit" that's supposedly designed for their particular car. In fact, many of the bushings on Triumphs are "universal" type that can be bought by size, or at least close enough to trim to fit. Urethane can be machined, shaped or trimmed in various ways, generally with a low speed, sharp cutter to avoid friction and melting. So, if a particular "kit" doesn't appear to be available, or you want a softer or harder bushing than you see in kit form, or you just don't like the fit of a particular bushing in a kit, it's possible to order them by size or close to size and then trim to fit. (This isn't possible or is more difficult with some cars, such as Land Rover which use a number of really huge bushings in their suspensioni, most of which really need to be specially made). There are even blank "rods" of urethane material available to work with. Superflex (for one) sells these in four different hardnesses.
Hope this helps!
PeterK
Yoda
Offline
I bought a standard grease gun size tube of Prothane Supergrease, enough to last several lifetimes. Think I paid around $20 for the tube. This stuff is really sticky and hard to remove from your hands so it should last a while.
They also sell a 3 pack small sachel of the stuff for $5.
Summit racing https://store.summitracing.com/egnsearch.asp?N=700+400351+115+317449&autoview=sku
If there was an easy way to mail some to you,
They also sell a 3 pack small sachel of the stuff for $5.
Summit racing https://store.summitracing.com/egnsearch.asp?N=700+400351+115+317449&autoview=sku
If there was an easy way to mail some to you,