SRX / XT600 crankcase bearing held by three screws... removal?

[guest1972]

Ello

I have three (count 'em) crankcases to disassemble (long story). One SRX and two XT cases (all 600s).

I am on my second. Both times those three screws rounded on me. Clearly I am not doing it right.

Have tried:
- impact driver (hit with hammer type)
- impact wrench (electric type)
- a socket on a 3/8 driver and a lot of leaning
- all of the above cold, and hot (100 C)

I heated the cases to 100 C by warming the oven first, then sticking the case half in for 1/2 hour. I am thinking I may not be hot enough, or have had it in long enough.

Practical tips, voodoo, juju, or any other type of black magic most welcome.

Help.

B

[themoudie]

Aye Baz,

When dismantling 'Sally' I used a well fitting long screw driver and was pleasantly surprised. Whether a locking fluid had been applied during manufacturer assembly, I can't say, a previous owner may have been inside afore me.

However, if either 'green' or 'red' Loctite 270 threadlocker has been used the following link to the appropriate Loctite page is below:

Loctite_270_spec_sheet

N.B. Dismantling details for both types of liquid are on page 2 of their respective data sheets and suggest "localised heating to 250°C and removal whilst hot"!   

I have also checked the data sheet for Loctite 222, which is an "easy disassemble with hand tools" thread locker and the same method and temperature are recommended as for the Loctite 270.

Appears delicate work with oxy/acetylene maybe required or a competent local engineering workshop. 

What weight of hammer did you use with the impact driver? A 2lb ball pein, with a long handle maybe required! 

I hope that you are successful.

My regards, Bill

[guest1972]

Thanks Bill.

Hmmm... I am currently practicing on my 'spare' set of SRX cases - the ones with the crack in them. They are destined for experiments in case polishing, and then will be melted down. So, I after some attempts at moderate bashing with the impact driver, I did feel like I belted the bejesus out of them - all I succeeded in doing was rounding the screw.

I certainly don't want to do that with my 'good' cases...

250C is pretty hot for ally, probably going to mess with the tempering. I suspect I'll end up drilling the b*stards out.

I will be replacing those phillips head screws with some proper countersunk hex socket heads, and also their equally annoying cousin that refuses to release the clutch cam rod thingo. Phillips head is OK for wood but should be banned for use with metal. [rant over]

B