Fitting Brake Master cylinder

[itchyfeet]

Never fitted one before.

Any pointers so I don't make school boy errors gratefully received

P1080926 by Paul_Barr, on Flickr

[captain Byrne]

Yes.. make sure you fill it with brake fluid first so it's well primed. The rest is pretty straightforward, have plenty of rags knocking around to wipe up inevitable spillages. Other than that it's just a straight swap.
Obviously bleed the system as you'll no doubt know.

[bigbadbob76]

Never done one on a T25 but done a couple on cars and it's pretty straightforward.
(except on the wife's old renault, i had to do it through the pedal plate cos it was hidden behind the engine. )
obviously you want to drain the level down a bit first so you don't get fluid everywhere, the fluid attacks paint something hellish.
Don't drain down any more than you have to or it makes bleding the system more difficult. just down to below the outlets is good.
You'll get some drips anyway so covering things up in that area is worthwhile.

[nevill3]

I remember doing mine on an early (1983) 1.6D and found that there was an extra hole in the new one compared to the one that was on. ( It is for an extra "brake failure sensor??) I couldn't get a blank for it so I just inserted another brake switch sensor as a bodge!

[volks_womble]

It's not a bodge... the US models have 2 brake light switches in case of failure. There is an additional socket on the loom for a second bake light switch...

What I would say is - do not over tighten the brake light switch, as it splits the boss (and is why I now know how to change the master cylinder...)

[itchyfeet]

Thanks for the tips

[slowcoach]

It's not a bodge... the US models have 2 brake light switches in case of failure. There is an additional socket on the loom for a second bake light switch...

What I would say is - do not over tighten the brake light switch, as it splits the boss (and is why I now know how to change the master cylinder...)

Oh! Makes sense now. Mine has two sensors connected and is an oz model. Three pin switches too, which confused brickwerks at the time

[itchyfeet]

It's not a bodge... the US models have 2 brake light switches in case of failure. There is an additional socket on the loom for a second bake light switch...

What I would say is - do not over tighten the brake light switch, as it splits the boss (and is why I now know how to change the master cylinder...)

not just us models, my late vans both have two switches

P1060232 by Paul_Barr, on Flickr

[itchyfeet]

Fitted this today, pics as usual

clocks off and check the old one looks like the new one before removing it, had wrong parts before

P1090096 by Paul_Barr, on Flickr

top off and filter out

P1090102 by Paul_Barr, on Flickr

syphon off the fluid

P1090101 by Paul_Barr, on Flickr

I could not believe the black dirt at the bottom

P1090104 by Paul_Barr, on Flickr

clutch master cylinder feed off

P1090105 by Paul_Barr, on Flickr

goes to clutch master here, that will need bleeding later too.

P1090099 by Paul_Barr, on Flickr


brake switch connections off and then 11mm spanner removed1st brake pipe, bit of tube on so nothing gets in

P1090107 by Paul_Barr, on Flickr

then the other brake pipe off

P1090108 by Paul_Barr, on Flickr

then you can release 2x m8 nuts

P1090109 by Paul_Barr, on Flickr

and it comes off

P1090110 by Paul_Barr, on Flickr

[itchyfeet]

Pulled the reservoir off, best wear goggles it went suddenly and sprayed me with brake fluid

plugged holes, added some fluid and shook it to release the dirt

P1090112 by Paul_Barr, on Flickr

refitted clean tank to new cylinder, swapped switches over, these are tapered thread so don't want to be silly tight.

P1090114 by Paul_Barr, on Flickr

refitted it and filled reservoir
I didn't fill the cylinder I wasn't sure how to without it pouring out all over the dash

P1090116 by Paul_Barr, on Flickr

pressure bled kit on, tyre down t 15psi

P1090117 by Paul_Barr, on Flickr

went round once but air was still inside, so I went around again but this time I pressed the pedal while it was bleeding, then bled the clutch and finally went around one last time.

each fill of the pressure bleed bottle is 0.5 litres, best not to let it run out or you get lots of air bubbles, stop just before release tyre pressure and refill.
I put 1.5 litres through.

P1090118 by Paul_Barr, on Flickr

refitted clock and test drove it, seems fine now

[colinthefox]

Itchy

Thanks for that, a really good clear explanation.

[Oldiebut goodie]

While you were there, did you happen to notice where the fluid level connector drops down to when it falls down? Can't find mine for love nor money after last fluid change!

[itchyfeet]

While you were there, did you happen to notice where the fluid level connector drops down to when it falls down? Can't find mine for love nor money after last fluid change!

where it ends up is any bodies guess but this is the cable, may help to find it?

level sensor cable by Paul_Barr, on Flickr

[itchyfeet]

Itchy

Thanks for that, a really good clear explanation.

Thanks for he encouragement

[Oldiebut goodie]

Thanks -I am very wary of pulling on just any cable in there given how delicate the wiring is. Knowing my luck something else will get disturbed.