Rear wheel brake cylinder seals - what's the polo for?

Post by **Meekcome** » Sat Sep 16, 2006 9:59 am

Hi, just received a repair kit for a 1098cc traveller rear wheel cylinder (MOT failure

). The dust cover boot is self-explanatory, the slim o-ring I can see replaces that on the cylinder piston, but whats the thick black rubber 'polo' for? Do I need it? I can't see anything similar in the brake pipe union/bleed nipple assembly on the car at present.....
thanks for any advice.....

Post by **hamster** » Sat Sep 16, 2006 10:16 am

The slim o-ring is just a dust seal on the handbrake piston.
To remove the hydraulic piston you need to remove the handbrake lever, then remove the hydraulic piston which sits further down the bore.
When the hydraulic piston is out you can change the hydraulic seal. If you are lucky, one of the seals in the seal kit will fit... There are different seals depending on age of the Minor (or type of replacement cylinder that theoriginal was replaced with. The patern cylinders often have different seals to the non-pattern parts)
Replacing the hydraulic piston needs to be done with care otherwise you will cut the new seal (it can get cauught in the slot for the handbrake lever)

Best option is to replace the cylinder itself - only about £12.

Post by **bmcecosse** » Sat Sep 16, 2006 7:14 pm

I agree - just fit a new cylinder - in fact best to renew both sides tehn you won't have to worry about them for a few years. if the shoes hav been contaminated with leaking fluid - then new shoes too. And check the handbrake cables and the clevis connection are all in top nick while you are down there!

Post by **Meekcome** » Sun Sep 17, 2006 1:34 pm

Thanks guys. I replaced the seal in the cylinder, bled the system, but it still leaks

. So I see original cylinders selling for £25, pattern ones for a tenner (prices from ESM spares). The ol' girl only does around 500 miles p.a, so I'm thinking pattern parts might do....any last thoughts on that?

Post by **hamster** » Sun Sep 17, 2006 3:57 pm

I'm thinking pattern parts might do....any last thoughts on that?

The pattern parts are more difficult to bleed due to the seal design (round the piston instead of a cup on the end of the piston). This allows more air to get trapped in the cylinder.
If you fill the cylinder full before fitting you shoulkd be ok.

£25 sounds a LOT for a non-pattern part, but maybe that's life these days!

Post by **Onne** » Sun Sep 17, 2006 4:39 pm

Go for the genuine lockheed ones wherever you can. Lots and lots better IMHO.

Post by **bmcecosse** » Sun Sep 17, 2006 6:59 pm

But even the 'genuine' parts for a Minor are so cheap compared to rip off price parts for modern cars. I rather think the pattern parts will be fine for you - if I didn't have a small pile of spare cylinders - I would fit the pattern ones if forced to buy.

Post by **Relfy** » Tue Sep 19, 2006 9:41 am

I've just replaced one rear cylinder with a pattern (no money left after changing the master cylinder and two fronts with Lockheed!!) - although I can't speak for longevity - it bled fine the first time.