Hydraclamp seal

[Matchless?58]

Hi , I have to replace the seals in one of my hydraclamps which is leaking badly . I have already got the seals and intend to replace the seals over the Christmas break .( Now Essex seems to have gone into total lockdown might be a bloody long break ).
Anyway bit of advice needed please . List of questions below .
1/ do I unlock the hydraclamp lever to do this job ?
2/ what position should the backhoe be in? Commen sense says securely on the floor but it is the position I would like to know .
3/ undo big bolt in center to remove ?
4/ will I loose much oil ? I intend to fit plugs into the ends of the hoses .
Can't think of anything else but any hints and tips will be welcome .
Cheers Chris

[agrimax]

Hi Chris,Slide the boom to whatever side will give you the best access to the back of the big bolt should you need at it. Very often when you go to loosen the retaining nut,the bolt turns too.There is a piece of steel welded in place to prevent the bolt from turning but it becomes worn and doesn't do its job.Access isn't the best for welding something else on...You may need big heat on the nut but there's a plastic spacer in the clamp between the seal and the carriage rails,which you don't want to melt! Any messing with mine,I just cut the nut as close to the threads with a grinder and then split with a chisel and put a new one on with copper grease.They're not expensive,nor are the bolts but not much use under the current lockdown...Hopefully you'll be lucky and it'll loosen.
Set the bucket on the ground just to take the weight off the clamps and unlock to release any pressure.There shouldn't be much of an oil loss. When you get the clamp off,lift out the spacer and you should be able to prise out the seal with a small pry bar or strong screwdriver,but it can be tight. The new one will hammer in or you can start it by clamping in a vise.

[Matchless?58]

Thanks so much for that comprehensive reply and for taking the time to write it ! Like I said I am going to tackle the job soon and this advice is really appreciated .
Have a good Xmas no matter what you will be doing .
Best regards Chris

[gecko.cx]

Thanks for the thread - I was going to ask exactly the same questions.

I don't have a 2-1/4" (57mm) spanner, so was planning to make one with the new plasma cutter. After reading the reply above, I'll make it a bit heavier than I originally intended!

[gecko.cx]

Had my first attack on this one today.
As expected, with the boom supported and pressure released, the bolt would spin freely.
Adding a 3mm shim between the bolt head and the stop just got dragged through.
Adding a 4mm shim did the trick.

Once apart, it became apparent I should have wound the nut off two turns at a time and applied hydraulic pressure to move the piston out squarely (repeating until free). As it was, I managed to pop it once separated, but it came out skewed, so there was still a struggle.

I've added a load of weld metal to the backing plate lug, so hopefully next time it'll be more cooperative.

[Matchless?58]

Thanks for the update Ian .
I haven't had time to get stuck into mine yet as I got involved in finishing the resto of my ajs motorcycle . I thought I would be able to do both things over the Christmas break but as usual time seems to get away from me when I work on bikes . Nearly done now . So JCB next although - zero here ATM !
Re your problem with getting the seal out after removing hydraclamp . I am going to try blocking up one of the hydraulic oil supply holes and attaching my air compressor hose to the other one . Just to see if that will push it out with out damage . It may not work but worth a try . Your experience with the turning bolt seems to be a common problem when trying to do this job so I'm fully expecting this with mine . Good tip about adding the weld .
Cheers Chris

[gecko.cx]

If you use the air compressor, leave the clamp mounted with the nut on a couple of turns. The seal is quite heavy and will do some damage if it flies across the workshop!

[Matchless?58]

Thanks mate point taken !
Cheers Chris

[MrF]

Ive got a grease gun adapted to pump hydraulic oil that I use for this sort of thing. Its much more controlled than firing caliper pistons (its usual use) round the bench etc

[Slooby]

Ive got a grease gun adapted to pump hydraulic oil that I use for this sort of thing. Its much more controlled than firing caliper pistons (its usual use) round the bench etc

But removes the adrenaline rush you get from the 'jack-in-the-box' effect of not knowing when it's going to 'let go'