Brake and clutch master cylinders

Post Reply
User avatar
Wally2
MMC Member
Posts: 1693
Joined: Sun Jul 29, 2012 20:02
Location: Belper, Derbyshire

Brake and clutch master cylinders

Post by Wally2 »

I have the plastic canister type brake and cltch master cylinders and I am getting leakage on both. I dont think the leaks are from the cylinders themselves but from the plastic screw tops, I suppose with the car bouncing around on our wonderful roads the fluid will splash up to the tops. the fluid tends to run down the sides and off the bottm onto the munting brakect and car bulkhead where it is efficiently removing the paint! There is not much of it but enough the make the paint bubble up. As a trial I have removed some of the fluid down to 3/4 between low and full marks to see if it helps.
Two things 1) has anyone else had this problem with these types of cylinders? and 2) anyone know of a brake fluid resistant paint?
Cheers
Chris
Chris
WEEMOKE
JUX180D
User avatar
grantourer
MMC Member
Posts: 1125
Joined: Fri Dec 31, 2010 15:55
Location: Kenilworth. UK

Re: Brake and clutch master cylinders

Post by grantourer »

Hi Chris. never heard of that one. I use Silicon fluid, rather than traditional fluid, it is non hygroscopic (does not absorb water) and does not hurt the paint.
Regards, Graham & Judith
1981 Aussie Moke
1989 Portuguese Moke
1979 Clubman Estate
User avatar
Wally2
MMC Member
Posts: 1693
Joined: Sun Jul 29, 2012 20:02
Location: Belper, Derbyshire

Re: Brake and clutch master cylinders

Post by Wally2 »

Hi Graham,
Not heard of silicon brake fluid, presumably you'd have to bleed out the existing fluid to change to silicon, would the seals have to be changed as well?
Chris
Chris
WEEMOKE
JUX180D
User avatar
grantourer
MMC Member
Posts: 1125
Joined: Fri Dec 31, 2010 15:55
Location: Kenilworth. UK

Re: Brake and clutch master cylinders

Post by grantourer »

Hi Chris. Silicon fluid is DOT4 and normal brake fluid is DOT3 specification, not sure what DOT stands for. My system was replaced when the Moke was repainted.
Regards, Graham & Judith
1981 Aussie Moke
1989 Portuguese Moke
1979 Clubman Estate
User avatar
Wally2
MMC Member
Posts: 1693
Joined: Sun Jul 29, 2012 20:02
Location: Belper, Derbyshire

Re: Brake and clutch master cylinders

Post by Wally2 »

Hi Graham,
From tinternet ''­The three main types of brake fluid now available are DOT3, DOT4 and DOT5. DOT3 and DOT4 are glycol-based fluids, and DOT5 is silicon-based. The main difference is that DOT3 and DOT4 absorb water, while DOT5 doesn't.''
Chris
Chris
WEEMOKE
JUX180D
User avatar
Wally2
MMC Member
Posts: 1693
Joined: Sun Jul 29, 2012 20:02
Location: Belper, Derbyshire

Re: Brake and clutch master cylinders

Post by Wally2 »

Also
''Two other important things about brake fluid: DOT3 and DOT4 eat paint, so don't spill either of these on your car. Also, none of the different types of brake fluid should be mixed. They can react badly with each other and corrode your brake system.''
So presumably you cannot change from DOT3/4 to DOT5 without changing the complete system.
Chris
Chris
WEEMOKE
JUX180D
User avatar
Wally2
MMC Member
Posts: 1693
Joined: Sun Jul 29, 2012 20:02
Location: Belper, Derbyshire

Re: Brake and clutch master cylinders

Post by Wally2 »

Graham,
What colour is your brake fluid? as:-
''DOT 3
Glycol Colorless to amber
Passenger cars and trucks

DOT 4
Glycol
Colorless to amber
Passenger cars and trucks

DOT 5
Silicone
Purple
Military and show vehicles

Chris
Chris
WEEMOKE
JUX180D
User avatar
fistral fig
Posts: 130
Joined: Thu May 26, 2011 17:42
Location: Chipping Ongar, Essex

Re: Brake and clutch master cylinders

Post by fistral fig »

Hi Chris, I have used silicon fluid in my newly rebuilt Mk1 mini and the system was dry with most parts being new anyway, I tried to find out wether you had to replace all the seals etc, and spoke to some people who said they have only drained the old out and replaced with the silicon and all was OK, but I would like to change the Moke over as well and can not find any info on its definatley ok to change just the fluid!
By the way silicon is as you say purple and is DOT5 (not DOT4 as Graham suggested).
Just as an added confusion there was some years ago a synthetic fluid which was designated DOT 5.1 and when I was trying to buy some silicon locally they thought that was what I was after as they had not heard of silicon either. had to get it from the internet in the end. ...........FF
User avatar
Dean
MMC Member
Posts: 1801
Joined: Tue Oct 12, 2004 10:28
Location: Jimboomba, QLD, Australia.
Contact:

Re: Brake and clutch master cylinders

Post by Dean »

They don't seem to sell DOT3 over here any more, it's all DOT4 which I have seen coloured both green or amber.
Dean
User avatar
grantourer
MMC Member
Posts: 1125
Joined: Fri Dec 31, 2010 15:55
Location: Kenilworth. UK

Re: Brake and clutch master cylinders

Post by grantourer »

Hi Chris. I got my DOT's wrong, it should be Silicon is DOT 5. Just wash seals etc. in Silicon to clean them rebuild and refill, this is what I have done in the past. So far I have used DOT 5 on 2 minivans, 2 Clubman Estates, and 1 Moke. With no problems.
Regards, Graham & Judith
1981 Aussie Moke
1989 Portuguese Moke
1979 Clubman Estate
User avatar
Wally2
MMC Member
Posts: 1693
Joined: Sun Jul 29, 2012 20:02
Location: Belper, Derbyshire

Re: Brake and clutch master cylinders

Post by Wally2 »

Hi Graham,
Sounds a good idea but I've just had new drum cylinders all round for MOT. Might be easier to cure the leaky master cylinders!
After a couple of long runs over the past couple of days with the fluid level reduced, the leak seems to have stopped, so maybe it is the tops weeping, not sure if you can buy just the tops will have to look round.
Thanks for all the sugestions.
Chris
Chris
WEEMOKE
JUX180D
User avatar
Doug G
MMC Member
Posts: 5096
Joined: Sun Sep 17, 2006 14:44
Location: Caribbean

Re: Brake and clutch master cylinders

Post by Doug G »

grantourer wrote:Hi Chris. Silicon fluid is DOT4 and normal brake fluid is DOT3 specification, not sure what DOT stands for. My system was replaced when the Moke was repainted.

The DOT part refers to the U.S. Department of Transportation, which issues detailed standards for all motor vehicle brake fluids in the country.
Having a moking good time!
User avatar
grantourer
MMC Member
Posts: 1125
Joined: Fri Dec 31, 2010 15:55
Location: Kenilworth. UK

Re: Brake and clutch master cylinders

Post by grantourer »

Thanks Doug, now we know.
Regards, Graham & Judith
1981 Aussie Moke
1989 Portuguese Moke
1979 Clubman Estate
User avatar
Robin Jones
Posts: 655
Joined: Wed Aug 08, 2007 20:02
Location: Maple Heights/North Royalton, Ohio, USA

Re: Brake and clutch master cylinders

Post by Robin Jones »

I don't know if the "usual suppliers" have straightened it out yet. But, a few years back, you would be lucky to get one month from the brake switch if using DOT 5 silicone.
This is Matt Jones Son of Robin.
User avatar
Wally2
MMC Member
Posts: 1693
Joined: Sun Jul 29, 2012 20:02
Location: Belper, Derbyshire

Re: Brake and clutch master cylinders

Post by Wally2 »

Think I may have cured the problem! Bought two new plastic caps from Somerford minis and they, along with the reduced fluid level seem to have stopped the problem. Just need to repair the damaged paintwork now!
I have ordered some brake fluid resistant paint from e-bay which I will apply all around the reservoirs and hope that will be an end to it.
http://www.ebay.co.uk/itm/390567397061? ... 1672wt_976
Chris
Chris
WEEMOKE
JUX180D
Post Reply

Return to “Steering/Suspension/Brakes/Wheels/Tyres”