How long does a MC rebuild last?

[tedtaylor]

What did I do wrong? I rebuilt my '73 Elan Sprint master cylinder last year and with only just 1,000 miles under my belt, the MC is leaking through the back seal onto the firewall.
I did not sleeve the unit, only a very slight honing. Used typical rebuild kit from the usual supplier. Perhaps I needed to coat rubber seals with red brake grease?
Has anyone else had short life span on their rebuilt MC's??
feedback please!

[patrics]

Hi Ted
What master cylinder is it?

Couple of points
If the cylinder was originally worn then honing isn't going to fix that
Quality of seal kit?
Contamination

Regards
Steve

[tvacc]

Wrong brake fluid? Only use Castrol.

[512BB]

You assembled it dry and tore the rubbers when first operated?

Leslie

[Orsom Weels]

Very possibly could just be the quality of the materials used in the manufacture of the seal kit. Modern rubber components just don't seem to be up to much now. I've had a batch of master cylinder kits for Norton Commandos fail very early their life, it's almost becoming an annual job to replace them. I've tried different brands of fluid, all to the correct spec, but that doesn't seem to make any difference. The only constant is the seal kits & as there's only one or two manufacturers of such things choice is limited.

Regards,Tim

[pharriso]

Ted, as a point of reference, I rebuilt my master with a kit from Ray in April 2014, still good!

That's 4 seasons & 1,200 miles.