Burman B52 'box end cover bushes and seals

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REW
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Burman B52 'box end cover bushes and seals

Post by REW »

The gearchange U shape spring broke today causing me some fun in the middle of navigating a roundabout. Anyway, end cover off and I feel I should replace the gear change shaft bush too as it is loose and leaks more than I would think a new seal alone would cure. Are these bushes a tap out or heat in the oven and whack hard sort of fit?

There are several helpful articles and posts on the subject but none quite tell me how tough the bushes are to remove. Any advice (steady)?
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Ron

1951 Matchless G3L thumping round the Durham Dales.
oldandsmelly
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Re: Burman B52 'box end cover bushes and seals

Post by oldandsmelly »

I've replaced a couple of these and I've always found them easy to knock out. There might be a bit of resistence at first, but once on the move they come out OK.

I always warm the case a little and I use plumber's freezer spray on the bush. I'm not sure if this helps or whether I'm wasting my time doing it but I've not tried it without.
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Re: Burman B52 'box end cover bushes and seals

Post by 56G80S »

Ron

Quite some time ago I replaced all the bearings and bushes in a B52 and from my (fading) memory I also warmed the case in the oven although not to a high temp, drove out the bush and put the new one straight out of it's overnight rest in the freezer straight into the case while it was warm.

Same as oldandsmelly whether this is necessary or not I don't know but I felt more comfortable that way.

That box is going in over winter so I can overhaul the (working OK but had a hard life) AMC box.

Johnny B
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REW
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Re: Burman B52 'box end cover bushes and seals

Post by REW »

Thankyou both. On another related topic - this picture from Christian's archive suggests using fibre washers under the cheese heads of the cover screws: http://archives.jampot.dk/technical/Tra ... ebuild.pdf

They are not listed in the spares lists - does anyone bother with this refinement (embellishment)?
Ron

1951 Matchless G3L thumping round the Durham Dales.
oldandsmelly
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Re: Burman B52 'box end cover bushes and seals

Post by oldandsmelly »

I do use fibre washers under the cheesehead screws just as a matter of habit. I'm not sure if they are necessary or not, I guess it depends on how damaged the surface is where the cheesehead screw abuts.

I've never had oil leak issues from the gearbox cover, maybe I've been lucky. The other end of the box is another thing entirely and sealing the mainshaft and high gear bits has been an ongoing struggle. I've come round to the idea that I'm using too thin an oil - Mobil 0/40W and am going to try and get some straight 50W.
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REW
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Re: Burman B52 'box end cover bushes and seals

Post by REW »

Buoyed up by comments I have now had a go and it is very easy to knock out the bushes. No heat used, a 1/2" socket extension bar given a very firm first tap with the end cover held in left hand on the workbench. Once started indeed it comes out easily - just the weight/inertia of the cover providing resistance to the hammer taps. A 1/4" drive 5BA socket for the gear indicator spindle worked well there. To replace them I will shrink them in the freezer and lube well with moly grease.

Worst wear is actually in the gearchange quadrant axle which is a bit of a bugger. Contemplating the value of a new one... It is odd that the oil seal is inside the cover which means the shaft/bush is only lubed if there is leakage! Not the case on the kickstart axle or spindle shaft.
Ron

1951 Matchless G3L thumping round the Durham Dales.
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Rob Harknett
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Re: Burman B52 'box end cover bushes and seals

Post by Rob Harknett »

oldandsmelly wrote:I do use fibre washers under the cheesehead screws just as a matter of habit. I'm not sure if they are necessary or not, I guess it depends on how damaged the surface is where the cheesehead screw abuts.

I've never had oil leak issues from the gearbox cover, maybe I've been lucky. The other end of the box is another thing entirely and sealing the mainshaft and high gear bits has been an ongoing struggle. I've come round to the idea that I'm using too thin an oil - Mobil 0/40W and am going to try and get some straight 50W.
I'm sure 0/40 would be too thin, not checked but I use 50 in engine and gearbox.
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Re: Burman B52 'box end cover bushes and seals

Post by 56G80S »

I use SAE50 in the AMC and Burman B25.

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REW
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Re: Burman B52 'box end cover bushes and seals

Post by REW »

New bushes now in - easy to do with a good thump with a hammer and suitable socketry as a drift. Pre - cooled in the freezer but I suspect the moly grease more important to aid "slip".

Now, the big U shaped leaf spring - pictures I have seen don't answer my next question. It is not the same shaped edge each side - one has a slight straight slope, the other a curve as well. Which way up should it go? My guess is curve (slightly larger cutaway) side to the inside ie gears side - am I right?
Ron

1951 Matchless G3L thumping round the Durham Dales.
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Re: Burman B52 'box end cover bushes and seals

Post by Rob Harknett »

Ashampoo_Snap_2017.06.27_23h55m37s_002_.png
Does this enlarged picture give any clues Ron. It does appear to have a curve where you guess it should be
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