Little help

[d-m]

Hi all I haven’t posted in a wile but I have been lurking about. I have been restoring a 62 Austin mini and it has had some challenges of course every chance I get to make a part I jump on. I started on the brakes a few months back and found the front wheel cylinders were junk yes you can but them but in the US there 117.00 ea. I decided to sleeve them. I ordered up some stainless seamless tubing of the right ID when the tubing arrived I measured the OD chucked the cylinder in the mill squared the bore and bored, leaving .002 press fit, froze the cylinder and assembled and drilled the bleed and inlet holes. After finishing honing it all seemed to easy. Today getting closer to having the mini done and only a few things left I decided to bleed the brakes every thing went well till I applied some real braking force to the system. And the front cylinders started leaking. I removed one cylinder and removed the pistons and left the .937 cups, filled with the cylinder with Fluid and with air pushed them up against the jaws of my vise
To my surprise the fluid was not coming from the cups but was being forced out from between the sleeve and the cylinder wall. I use sleeve and bearing lock tight on the surfaces before I pressed them in. Any one else have any experience in doing this sort of sleeve I would like to know what I did wrong
Thanks Dave

View attachment New Image.BMP

 

[Stan]

I would like to know what I did wrong

Working on an Austin Mini?

 

[d-m]

???
Thanks for the encouragement
Stan

 

[d-m]

Working on an Austin Mini?

I should have seen that comming :wall: :wall:

 

[Bernd]

d-m,

PM sent to you.

Regards,
Bernd

 

[RICHARDDV]

i have had considerable experience resleeving hydrostatic valves in farm machinery with working pressures of the 10k psi range. Your procedure sounds correct. the problem is the pressure is getting under the sleeve at the inlet and vent holes. you need to create a pressure dam between the inlets and the outer end of the cylinder. you can do this by cutting an annular groove on both sides of the inlets to create a reservoir of sealant to stop the brake fluid from migrating out. also make sure that the loctite that you use is high strength wicking type and make sure that it is alcohol compatable. Another possible procedure is bore to a thumb press fit and use JB weld epoxy and cure 24 hours---hope this helps richard

 

[d-m]

Thanks Richard
My thoughts on the pressure dam would be to use a rotary bur and create the reservoir area is this the proper way ?
I like the light press fit with the JB weld as I can still drill my inlet and outlet ports. Also I can easily get to that point from here with a hone I think this is the way I will fix it but would like to know the way to make the dam.
Thanks again
Dave

 

[RICHARDDV]

use a small boring tool to cut a concentric groove around the bore just as if you were going to install a snap ring in it. Butter the sleeve up liberally with the epoxy so the excess will be trapped in the grooves when the sleeve is pressed into the bore.
Another possible repair is to bore the cylinder and install a 1.00" sae kit in it. you would need to machine new cup followers but it would be another viable repair providing the pitting would clear---richard

 

[d-m]

Thanks again Richard
Trying to get to sleep disappointed in the fact that my clever little plan failed it come to me that you would just bore the relief as you described.I also thought of boring it too 1.00 but it will be faster to resleeve with the dam then making new cup followers.
Thanks to every one who has replied to help
(even you Stan with your words of encouragement Rof}
Dave

 

[RICHARDDV]

good luck -richard