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MG MGB Technical - leaf-spring lubrication
|My MGB gt (78) has been laid up for 5 years and I am gradually getting it back to reliable running condition. With storage the rear road springs have the usual rust deposits between the leaves, can anyone suggest whether they should be lubricated and if so what should I treat them with|
|I always think you need the lubricant to penetrate a long way to the centre of the leaves. I wire brush the edges, they collect a lot of mud, then spray with 3 in 1 penetrating oil, then paint the edges with whatever engine oil I have around,they also do get sprayed with Dintitrol 3125 when the entire car gets done, but that only claims to penetate 3 or 4 mm|
|Lot of work I know, but if it has been laid up a while, why not dismantle them? You can then check for cracks in the leaves etc put it back together with some new bushes (the old ones might have dried and perished etc. ) But warning, the front leaf bolt will most likely have seized, mine had, what a job, I had to grind the spring eye, yes new springs. Hmm, perhaps you had best lube!!! Mike Doust|
|Try liberal squirts of Duckoil, then run the car a few miles and do it again, this will stop squeaks etc.|
Just done my MGC and all noises have gone.
For those of us on the other side of the pond. What is Duckoil?
|What about springs with interleaf strips? They should not be lubricated, I guess?|
|This is duck oil. Good stuff.|
|Spot on David that is exactly what I am using including the free squirter, if you shop around you will get a better price as well.|
Tore, my 'C'has interleafing and all seem ok, it hasn't desolved it and they all look in tact.
|I used Waxoyl painted on (interleaved springs) then ran a heat-gun over them to melt it into the crevices. With one application and a few miles the squeaking stopped. With new (or any springs that are off) I lay them on their sides and use the Waxoyl and heat-gun so it penetrates better, first one side then the other. With rubber bushes you want to avoid oil/grease products.|
Waxoyl has white spirt as the carrier so will swell the interleafing. White spirit gives off flammacble vapour and I would not recommend any one to heat springs with a heat gun, especially in the confines of a garage. Sounds as if Paul has the springs off the car and out in the open though.
Not done a Duckoil ingredients check but agree it is oily and the same thing may happen But in my experience using this product for 30 odd years I have not had a problem.
I'd recommend disassembling them, cleaning them, and then removing the rust with Naval Jelly, which contains phosphoric acid. Being a thick gel, it will cling to the surface being treated instead of running everywhere as would happen with an acid that is in liquid form. Phosphoric acid reacts very slowly with iron, thus hydrogen emission is much lower and hydrogen embrittlement of the metal is insufficient to present a significant structural problem that can result in the formation of cracks. Note that it will also react with the iron to form a dark-purple-hued, thin passivated layer of ferric chloride which will adhere to the surface. This is a natural result of chemical interaction. This protects the surface and also slows down the chemical reaction, so it is more or less self-limiting.
After removing the rust, rinse the naval jelly off thoroughly, then blow the metal dry with compressed air or your wife’s hairdryer (she will not mind you borrowing it for such a noble purpose, of course). Afterwards, paint the springs a nice dull black, then reassemble them with nylon strips at the ends of the springs. The nylon strips will never require lubrication
|Stephen, the passive layer must be iron phosphate, not ferric chloride!|
Ferric Phosphate is black, not dark purple, and remains as a top layer that can be easily scrubbed away.
|The on-car was indeed done outside, but seeing as how the Waxoyl is in contact with a large metal mass and melts pretty-well instantly I suggest the fire risk is minimal. The off-car was done in the garage but with the door open and the car outside ready for fitting.|
|Thank you folks for your advice. I have settled by spraying the springs with a spray grease manufactured by Comma. Although basically a grease, in spray form it seems to have good penitrating power, enough hopefully to lubricate the springs once I have driven a decent mileage. SI|
|Leaf springs inherently provide some damping from the friction of the leafs against each other. |
I would recommend the cleaning sited above, but not the lubrication. But practically the difference may not be noticeable between dry and lubricated.
|I'm having trouble getting the front bush out. i have the rubber out but the metal sleeve has remained in...what now? what nylon did you use between the leafs? Thanks,Rich O|
|Take a hacksaw blade and cut through the sleeve along the axis. Then use a punch or old chisel to push it inwards and it should peel off.|
|I will give it a try,thanks Art. Oh,what nylon was used between the leafs?? Thanks,Rich|
This thread was discussed between 23/11/2010 and 27/12/2010
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