Rear Suspension Housings - Worn

[kram350kram]

Speed -Sleeves are .011-.012 thick. There is a range specified on shaft diameters, so you would need to install on the bearing first then machine, your ID for a press fit. SKF will also custom make a sleeve base on your spec's. Now that would be bloody expensive! LOL

[TurboFource]

What if you repaired them with Devcon......it's made to repair equipment and machinable.

[Dilkris]

That's a good possibility well worth considering - never heard of it and in researching it just now see that "Devcon" make a range of products. I believe it would also key very well to the housing that has been "dimpled" in an attempt to decrease the bearing face ID - not sure about the one housing that hasn't. (You now have me thinking... )
So far not at the point of having to decide as I am still making the horizontal boring bar set up to line bore the housings, which I am going to need in any event.       

[MRN I J]

What if you repaired them with Devcon......it's made to repair equipment and machinable.

Or JB Weld, we have had good results with it

[SwiftDB4]

I'd be skeptical that even structural epoxy can restore worn housing bores. You might get a few months OK, but before long it will pound out. I've tried it for various short term fixes, but it doesn't last.

[Pfreen]

I hesitate to interject myself in this discussion since you seem to have a good understanding og the issue, but have you measured the two bearing diameters and the concentricity of the bores in the housing?  I don't recall seeing the numbers.

If the bores are just a few thousands of an inch large and the concentricity is good (I don't know a spec but the bearing manufacturers will have it), then why not use loctite sleeve retainer, which will fill gaps from .010 to .015" on diameter. 

[EuropaTC]

I'd be skeptical that even structural epoxy can restore worn housing bores. You might get a few months OK, but before long it will pound out. I've tried it for various short term fixes, but it doesn't last.

I think I'd agree. When I was working we had Devcon and similar products but we tended to look on them as short term fixes. Great to get you moving but some of the claims made by all the companies we considered as "optimistic". 

When all is said and done it's basically an epoxy resin with various filler materials but regardless of the filler, you've got to consider it as a thermosetting resin. Yes it's tough, yes you can machine it and even put in threads but it's not going to be as strong as the original steel or other metal.

Personally, for me with this application (hub carrier repair) a steel sleeve or Al weld/machine is the best repair option. Using Devcon or similar materials then machining for me  is no better than dropping the bearing in place over those dot punch marks and using one of the large gap filling bearing fit compounds - it's going to have the same result as far as bearing life goes.

When the time comes for new bearings the Loctite (or other bearing fit compound) will be simple to remove and replace again. It wouldn't surprise me if the Devcon broke up on removal, or if you're very unlucky, when pressing a bearing in to place if you went for the "add Devcon/machine to interference fit" approach. Back to square one.....

Incidentally, despite the above sounding like "Filled Epoxies are Rubbish" it's not really the my view. They are great to get you out of a hole and in some cases are permanent  repairs, you've just got to pick your application to suit.

Brian

[Dilkris]

Hello Dilkris,
I'm still wondering how that all works?! 
also, I spy a Zeus book!
Mark

It will all become apparent in future photo's - I hope    You have sharp eyes - it is a PRESTO reference "book" I've had for years - use it for thread tapping data.

[lotusfanatic]

I definitely spy a Zeus book! (under the Presto pocket book)

Mark

[Dilkris]

I definitely spy a Zeus book! (under the Presto pocket book)
Mark

I pulled them all out..... and you are correct - you have eyes better than an eagle!!   

[Dilkris]

Not on the same subject as sleeving or Loctite, but on the same component. I was working on the problem this afternoon when I stood back and looked at the housing in the lathe - and more to the point, how I had mounted it.

On the list of other things to do with these housings are of course the several stripped/badly worn 5/16" UNC tappings - as you all know there are 8 in each housing - 4 per side; interestingly they are machined on a common axis. (Unusual for Lotus to do something "normal..." 

Because I wanted room for adjustment on the "jig" I used 6mm stud bar to hold the housing in position - but upon installation of the housings to the radius arms, why not drill these fixtures out to 8.5mm (say) and use 8mm through bolts? (Note: the drill size, if I was to repair the damaged threads with 5/16" helicoils is 8.2mm )

Is this a common modification or is it not advised for some reason I have missed?

[jbcollier]

You would be putting tension on the mounting ears.  It would “probably” not be a problem but I don’t see an advantage to the through bolts.  I think it would actually be less secure.

[Dilkris]

I hesitate to interject myself in this discussion since you seem to have a good understanding og the issue, but have you measured the two bearing diameters and the concentricity of the bores in the housing?  I don't recall seeing the numbers.

If the bores are just a few thousands of an inch large and the concentricity is good (I don't know a spec but the bearing manufacturers will have it), then why not use loctite sleeve retainer, which will fill gaps from .010 to .015" on diameter.

I have between 6 and 12 thou oversize on the bearing housings, (this I can measure), so "yes" this falls into the tolerance of what Loctite says it does "on the tin". As regards concentricity, this is difficult for me to actually measure, however, in playing around and setting up one housing (vertical link) in my home made rig (see previous photo's), eccentricity in the 2 bearing housings clearly prevails - I can "see it" but I do not have the instruments to measure it - with my "eyecrometer" - I estimate this at 5 thou.

I find this interesting as I personally doubt (pre CNC) that these housings were originally machined under a line boring operation, (its very time consuming), and would probably have been done on a mill using the faces of the housings (twice remember) as the datum reference, this method of course could allow for eccentricity on 2 axis. 

The consensus of opinion on this subject appears to weigh heavily towards Loctite.

[MRN I J]

The concentricity doesn't matter too much right down to the last thousandth of an inch if you are boring & inserting a single housing, then boring for both bearings in one operation without moving it from the lathe (difficult), the brake drum / backplate can accept some tolerance becuase of the sliding cylinder

[Dilkris]

  I intend to bore for both bearings in one operation without removing the housing from the lathe.

My focus is on achieving a good fit and zero eccentricity for the 2 paired bearings; as you know, the 6206 is a single row deep grooved ball bearing and these will not be comfortable having to operate within an eccentric environment.