I have fitted a new output bearing (24-4065, C3) to the gear box shell of my WD M20 but unfortunately the bearing is not a very tight fit. It did not take a lot of pressure to place the bearing in the housing and I am concerned that oil may be able to leak between the bearing and the housing and then out past the sprocket.
There was no sign that the old bearing had spun in the shell.
Is there a fix for this issue or should I try and source another gearbox shell?
Many thanks, Neil
Hi Neil..Where are you located?...Ian
If you clean the area with clutch/brake cleaner and refit the bearing with Loctite bush and bearing fit, it should be good for ever. Most important these days is to fit a sealed bearing which is where most of the oil will leak through....I remove the inner seal for normal lubrication. Ron
email (option): ronpier@talk21.com
Hi Ian, I am in Australia, cheers Neil
Personally, I haven't found any of the chemical fixes fit for purpose.
The ideal fix is to make a thin liner to go in the bearing housing once it's been machined oversize and back on center.
Not easy to do even by experienced machinists from my experience.
Another way is to mask the new bearing with plastic washers bolted together and have it copper plated.
Even Nickle or whatever metal is being plated locally.
Mark
email (option): pes.sales@btconnect.com
Well it's worked successfully for me and even professional engine builders that I've watched over the years.
https://www.youtube.com/watch?v=qcknFHcTIeo[url/]
Ron
email (option): ronpier@talk21.com
I would go with a compound like loctite if faced with this scenario myself
If that was not successful / I would look for another shell & work with that - they are not that hard to find & considerably cheaper than any engineering work to recover the bearing housing area
Just my thoughts
Job
email (option): Jonnyob1atgooglemail.com
I guess it all depends on the standards your prepared to work too.
Mark
email (option): pes.sales@btconnect.com
Well these guys work to extremely high standards and still use Loctite and even take advice from Loctite.
Get your tea and biccies and a comfy chair.
https://www.youtube.com/watch?v=LEusm_xlgfA&t=3s[url/]
Ron
email (option): ronpier@talk21.com
In the case of an M20, if required, I'd say replacement of the gearbox case is the easiest option for most people if the bearing housing is beyond use....
Regarding the possible use of Loctite bearing fit (or similar) it's a case of determining what type/extent of wear/damage is present and deducing whether that falls within the range of what the bearing fit is designed for...The wear tolerances that the Loctite is effective for are laid down in the product specs....I've also found that an email to 'customer service' can be helpful in many cases...
Whilst on the one hand it is ridiculous to suggest there is no viable use for the product or that it should be avoided in every case, it is equally ridiculous to expect it to accomodate an amount of wear/damage that it's not designed for....There is a risk with all these products that it's easier to try and make it do something it wasn't made for than to carry out a repair or replacement when it's really needed....To misuse it moves into the area of 'bodging' IMO...The starting point should be to accurately measure and assess the wear/ovality of the housing and then look at the product specs....Then the right decision can be made...I'd bet money that loose bearing houses are rarely assessed using the correct methods at the outset as most people don't have the required measuring equipment to do that in my experience. Then the temptation is to go for the 'easy solution' whilst possibly ignoring the right one...One other thing that should also be considered...A C3 classification bearing has a larger internal clearance to allow for the fit in the housing and in some cases, warm operating conditions..A loose housing therefore negates the whole point of the C3 fit and in that case a standard bearing might be the better choice.....Ian
There was no sign that the old bearing had spun in the shell.
Is there a fix for this issue or should I try and source another gearbox shell?
Many thanks, Neil
As for fixing it, well loctite is a good option as long as the clearance it not too great. But years from now the next owner is not going to be happy when it has to be removed.
Shimming is also an option if you can accurately measure the bearing housing bore and the bearing itself. If you need to restore .002" of shrink fit an aluminum .002" shim wrapped around the bearing will work. And again you need to get it hot to fit.
Machining and sleeving the bearing bore is an even better idea. I have a machine shop at home but most people don't so you will need to take it to someone who does.
And finally, there is no shortage of old gearbox casings so maybe for you the best option.