Front hub bearing failure

[paddy]

Just found this Loctite 640 http://www.scparts.co.uk/index/lang-2/l ... 343250.htm (!0ml bottle @ ?21.08) It may be worth trying.

Thanks!

Paddy

[69S4]

I've already got a bottle of 638 (previously used on my rears) which is nearly as good but its effectiveness tails off after 150C but I think I might just go for that.

Paddy

Do you really need something with a high temperature spec? I presume you're using something like Castrol LM to lube the bearing and Castrol say 120C max for that. If the bearing is getting that hot you're much more likely to have a problem with the lubricant failing than the loctite.

[paddy]

Do you really need something with a high temperature spec? I presume you're using something like Castrol LM to lube the bearing and Castrol say 120C max for that. If the bearing is getting that hot you're much more likely to have a problem with the lubricant failing than the loctite.

Good question, and I don't really know the answer. I take the point about the max lube temperature. As Rohan says, the max temp for a road car will be considerably less than for a race car, but when you quantify the energy going into the brakes and the lack of specific cooling, and there being very little distance between the disc and the inboard bearing, I don't see why it wouldn't go well above 100C. Maybe I'm just paranoid.

Paddy

[rgh0]

The front disks on my Elan get to 600C when racing according to the temperature sensitive paint on some circuits. A road car going down a steep mountain may get to 300 or 400C if driven hard I would think. I use Castrol HTB ( High Temperature Bearing grease) in the front hubs of all my cars as under heavy braking even on the road you will be exceeding the the rating of coventional greases such as LM.

When i used loctite and peened the hubs the loctite had gone after one race meeting so the inner bearing races are getting up well over 200C when racing. On a road car may be alright if you dont have many mountains or hard stop go corners in your local but no real substitute for a proper fit.

I have always stayed with the cast iron hubs on my competition Elan rather than add lightness with alloy hubs. The bearing races loosen as it is under high temp conditions. In an alloy hub it would be even worse and it does not look like the makers have got the fit tolerances right for hot hubs.

cheers
Rohan

[paddy]

600C = 0.3mm differential expansion = ouch!

Paddy