Fitting Brake Master cylinder

Big lumps of metals and spanners. Including servicing and fluids.

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itchyfeet
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Fitting Brake Master cylinder

Post by itchyfeet »

Never fitted one before.

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

ImageP1080926 by Paul_Barr, on Flickr
Last edited by itchyfeet on 26 Dec 2017, 16:42, edited 2 times in total.
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captain Byrne
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Re: Any tips on fitting this?

Post by 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.
1983 LHD Westfalia poptop 1.9 DG petrol.

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Re: Any tips on fitting this?

Post by bigbadbob76 »

Never done one on a T25 but done a couple on cars and it's pretty straightforward. :ok
(except on the wife's old renault, i had to do it through the pedal plate cos it was hidden behind the engine. :shock: )
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.
'86 1.9 DG, 4 spd, tintop, camper conversion.
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Re: Any tips on fitting this?

Post by 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!
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volks_womble
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Re: Any tips on fitting this?

Post by 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...)
1989 1.9TDI (AFN) T3 Westfalia California

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itchyfeet
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Re: Any tips on fitting this?

Post by itchyfeet »

Thanks for the tips :ok
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Re: Any tips on fitting this?

Post by slowcoach »

volks_womble wrote: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
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itchyfeet
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Re: Any tips on fitting this?

Post by itchyfeet »

volks_womble wrote: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

ImageP1060232 by Paul_Barr, on Flickr
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itchyfeet
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Re: Fitting Brake Master cylinder

Post by 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

ImageP1090096 by Paul_Barr, on Flickr

top off and filter out

ImageP1090102 by Paul_Barr, on Flickr

syphon off the fluid

ImageP1090101 by Paul_Barr, on Flickr

I could not believe the black dirt at the bottom :shock:

ImageP1090104 by Paul_Barr, on Flickr

clutch master cylinder feed off

ImageP1090105 by Paul_Barr, on Flickr

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

ImageP1090099 by Paul_Barr, on Flickr


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

ImageP1090107 by Paul_Barr, on Flickr

then the other brake pipe off

ImageP1090108 by Paul_Barr, on Flickr

then you can release 2x m8 nuts

ImageP1090109 by Paul_Barr, on Flickr

and it comes off

ImageP1090110 by Paul_Barr, on Flickr
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itchyfeet
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Re: Fitting Brake Master cylinder

Post by itchyfeet »

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

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

ImageP1090112 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.

ImageP1090114 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

ImageP1090116 by Paul_Barr, on Flickr

pressure bled kit on, tyre down t 15psi

ImageP1090117 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.

ImageP1090118 by Paul_Barr, on Flickr

refitted clock and test drove it, seems fine now :ok
Last edited by itchyfeet on 26 Dec 2017, 20:48, edited 1 time in total.
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colinthefox
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Re: Fitting Brake Master cylinder

Post by colinthefox »

Itchy

Thanks for that, a really good clear explanation.
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Re: Fitting Brake Master cylinder

Post by 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!
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itchyfeet
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Re: Fitting Brake Master cylinder

Post by itchyfeet »

Oldiebut goodie wrote: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?

Imagelevel sensor cable by Paul_Barr, on Flickr
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itchyfeet
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Re: Fitting Brake Master cylinder

Post by itchyfeet »

colinthefox wrote:Itchy

Thanks for that, a really good clear explanation.


Thanks for he encouragement :ok
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Re: Fitting Brake Master cylinder

Post by 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. :D
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