MG Midget and Sprite Technical Fitting drums - Preventing future corrosion. BBS discussion at MG-Cars.net

MG Midget and Sprite Technical - Fitting drums - Preventing future corrosion.

I am installing new drums on the rear of my '66 with wire wheels. The machined flange on the hub extension mates with a machined surface inside the drum. What is the proper technique for preventing corrosion between these two components? Because they are machined surfaces I understand they should not be painted. I keep reading that anti-size is used on fasteners, but my concern in using it here is that even a light coating may run from the heat generated by the brakes and foul the linings. Perhaps a light smear of high temperature wheel bearing grease would be better, but I don't know. What about a gasket forming sealant to keep moisture out? The goal is to keep the flange and drum surfaces from rusting so the next time the brakes need to be serviced the drums will be easier to remove. Thanks, Paul

Paul Noeth

I do feel the need for protection and I am going to use anti-seize as suggested. If you haven't lived in the rust belt it may be hard to appreciate the damage that can be done in a short time. My car was on the road for only seven years and 62k miles. The car has been in dry storage since 1973. The attached photo shows the hub extension with white corrosion from the sacrificial zinc plating as well as red rust where the zinc has been depleted. The hub extension looks good after cleaning, but there are areas completely devoid of any plating protection. Those areas will corrode rapidly and that is why I feel some type of rust protection is advisable. I have not had any long-term experience using anti-seize, but everyone swears by it so it must work well. Does anyone know the theory behind it? Is the material copper powder suspended in a grease base? Does it protect metal by some type of electrolysis or cathodic relationship with the iron, or does it just do a superior job keeping moisture and oxygen at bay? Bernie, I think I remember the British Invasion Tour, at least advertisements for it. In '86 we had two small kids and entertainment money was tight so we didn't see it. I'm glad you had a chance to visit South Bend. It is a nice town with a lot of history, including automotive (and aviation) fame. Studebaker and Bendix were both located here once upon a time. And Notre Dame, it is quite a prestigious institution. No matter were you go, you'll always find Domers.

Paul Noeth

I am splitting hairs, but it's a fat one. Look at it from the point of view of someone who is an amateur auto mechanic, who never attended a trade school, never worked in a gas station or garage and decides to rebuild a 44-year old car from the ground up. The parts books warn that working on automobiles is inherently dangerous. I believe them. Especially if you unknowingly do something that causes the wheels to fall off. That same amateur mechanic also spends a significant amount of time reading old posts trying to learn the correct procedures so as not to have the phase "if he only knew what he was doing" included in his eulogy. He's learned two things, it is important to properly tighten fasteners, and not everything found on the Internet is gospel. Evidence this thread, once the corrosion issue was put to rest the seemingly simple question of, 'what is the proper torque on the nuts' comes up, and a range of 20 ft.lbs. to 40 ft. lbs. is returned. Either the torque on these components is not critical or specifications given may not be right. The fun part of this hobby is deciding which. My amateur opinion is both are true to some extent. My gut feeling is that I am not going to have a problem with the drum shifting on the hub extension, even when I lube the interface with anti-seize. Prudence also says the more torque applied to the fasteners the less likely the drum will be to shift. I've been warned to take anti-seize into consideration and not to over tighten the nuts, which could strip the threads. We assume the studs to be Grade 8 or better, and I have no reason to doubt that, but since there are no markings or documentation, it is still an assumption (re: ass-u-me). My generic torque spec for 3/8-24 lubed is 35 ft. lbs. with a note to reduce by 20% if anti-seize is used. A heretofore undisclosed fact is that the same supplier who provides the Grade 8 or better studs supplies a Grade 5 nut to go with them. (At least I think it is a Grade 5, see attached image). I am making another assumption (there is that word again) that in supplying a Grade 5 nut, the idea is that it is better option to strip the nut than damage the stud. A Grade 5 fastener with anti-seize according to a generic chart torques in at 20 ft. lbs. For the amateur mechanic this hair turns into a conundrum. A respected real world mechanic, with decades of practical experience, is tightening the nuts to 40 ft. lbs. without any issues. Opposed to that, other experienced people, along with manufacturer's specifications, are telling me that I will be in danger of damaging the nuts if I go above 20 ft. lbs. That's quite a spread which says to me that, in this case, torque is not critical at all. All things considered, I am going with the first SWAG I threw out of 28 ft. lbs. If anything breaks I'll let you know. As always, I appreciate everyone's comments; I've learned a lot. Thanks. Regards, Paul

Paul Noeth

This thread was discussed between 21/06/2010 and 25/06/2010

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