• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Disassembling frozen brake cylinders

Share this page

R

roger_abbott

Jedi Hopeful
Offline
I am trying to disassemble the brake cylinders on a 1951 Jaguar Mark V. The rubber seals have somehow welded themselves to the cylinders and compressed air will not budge them. The history of this car is that the second previous owner had the brakes rebuilt just before he sold the car to the previous owner some 30 years ago. The previous owner then dismantled the car for restoration, which is as far as he got. The brake cylinders sat around with whatever fluid remained in them all that time.

I've tried soaking the cylinders in parts cleaner for the last 60 days. No effect at all. I need something that will soften or dissolve the rubber seal without attacking the brake cylinder metal itself. Any suggestions?
 
Usually the piston seizes because of corrosionbetween the piston and the bore of the cylinder.Try first tapping the pistons inwards clean any rust or crud from the bore,being careful not to damage the piston and then try turning the piston keep repeating until it frees.If it won't budge,try replacing the bleed nipple with a grease nipple and pump it full of grease toforce the piston out.
 
The bad news is:
The pistons are most likely made of aluminum, and the bores cast iron. After 30+ years of sitting around electrolisis has taken it`s toll. In effect bonding the two dissimular metals in such a fashon that even if you do manage to seperate the pistons from the bores, the bores will be useless until re sleeved.
The good news MIGHT be:
One of the major hydraulics rebuilders may be able to either refurbish what you have or supply refurbished units. An email to one of these companys will supply a quick answer.
I used Apple Hydraulics to do some M.C. work for me and was very happy with the results. There are other hydraulic re- man supplyers of which I do not know the names. I`m sure others will chime in with names and other suggestions as well.
Kerry
 
AweMan is right. You are probably better off buying rebuilt units of even new. Not worth the frustration to find pock marks and pitting. The remnaufactures will reline the cylinders with stainless.
 
Thanks, guys, for the suggestions. I think my best bet is to send them off. They are not all that rare but they are expensive when you find them. I will try the grease gun idea on one cylinder to see what happens.

From examination, the cylinders seem to be made of cast aluminum (wild guess) and I think the pistons are steel, inasmuch as a pressed steel cap is spot welded to the end of the piston. It may well be that the pistons can't be seperated from the cylinders.

I'll let you all know how it comes out.
 
Back
Top