master cylinder

[pistolpete]

Hi all, I'm currently in the middle of changing the seals on the brake master cylinder. I may be missing something but the piston will not come out. I have removed the cirlclip and washer, and after 2 minutes of tapping it gently on the bench to encourage it , it started to get pretty forceful, so at that piont, I thought i better ask just in case I'm missing something. cheers pete

[AndyC]

Cleaned any corrosion away?

[pistolpete]

I have, I was thinking it screwed in !

[bash]

I havnt tsken the one off the lotus to pieces yet but I have dismantled loads in the past. Most of them have a locator pin in the back port. Lever off the reservoir and look down in the port and there will be the head of a pin visible, its only held in by the pressure of the spring in the back piston. Just pull the pin out with some snipe nose pliers. If it doesnt easily come out use the blunt end of a pencil (so it doesnt score the bore) to push the rear piston in slightly while pulling the pin.
The reservior will just push back in on reassembly.

Bash

[bash]

This diagram for a ford shows the offending pin
https://ford.7zap.com/en/car/78/no/0/1978/17153/74471/

Bash

[Esprit2]

The 'pin' does have to be removed before the piston can be withdrawn. However, it's more than just a pin you can abuse, it's actually a small valve that should be treated well. The piston hits it and tips it, causing it to vent... the 'Tip-it' valve.

Regards,
Tim Engel

[pistolpete]

Thanks, I looked at a number of youtube videos just to make sure I didn't mis anything simple , no one mentioned a little pin( valve), When putting it back do you just slide the first plugger back in and put the pin in?

[bash]

Correct, you may have to use the pencil to slightly compress the spring but it just drops in and as Tim says it does perform an important function. Make sure you slightly lubricate the bore and seals with some brake fluid to stop the new seal flipping over on its edge when you push the piston back in, which would equal no brakes.
Bash

[MetBlue]

Can't help on the cylinder, but I'd missed this thread.
I normally used the "active topics" quick link, but pretty sure this thread wasn't getting picked up.
Be interested to see if now I've posted on it, it shows on "active topics". Could be a glitch in the site ?
Tony

[pistolpete]

SO clearly Ive been slacking as Ive still not finished the Job, the reservoir seems tricky to get back in I cant get it pushed on the way down so its sitting on the metal casting, unlike other models there is no bolt or screw to hold it down. The best I can do is get it to a bout 2mm from the metal casting.. It therefor has a slight wobble..... SO what is the master cylinder from As Ive tried searching for it but there seems to be mention of a saab or land rover. This simple half hour job is a real pain