leak from the rear drum

Technical MGB discussion
Mario60
Posts: 45
Joined: Thu Jul 18, 2019 9:34 am
Forename: Mario
Surname: Sciriha
Location: Malta

leak from the rear drum

Post by Mario60 » Thu Mar 26, 2020 7:46 am

Hi,
Hope you are all OK and keeping safe.
I have discovered an oil leak on the back side wall of the tyre and on the floor. I have not dismantled as yet but I am thinking it is the wheel cylinder. What are your opinions? Is it a difficult job to change? Are there any tutorials available.
As usual many thanks for your help
Kind regards


Mario
Mario Sciriha
1972 MGB roadster
1971 MGB GT (for restoration)
1979 Honda CB650Z
1975 Kawasaki S1C 250
1974 Suzuki GT380
1979 Suzuki TS125

Ian Fozzard
Posts: 370
Joined: Fri Mar 27, 2015 8:18 am
Forename: Ian
Surname: Fozzard

Re: leak from the rear drum

Post by Ian Fozzard » Thu Mar 26, 2020 8:22 am

Hi Mario. Sounds very much like you have a leaking brake wheel cylinder. The procedure to replace these is well described in the workshop manuals available.
Just check the liquid and make sure it is brake fluid and not hypoid oil from the differential (hypoid oil has a very strong smell, brake fluid doesn't but is toxic- wear nitrile gloves).
The only real problem you may face is undoing the brake line union which attaches the metal pipe to the cylinder. These may be corroded or overtightened. Take care not to twist the metal pipe as you unscrew the union.
A few other points:
1. Place some polythene sheet under the master cylinder cap to reduce brake fluid loss
2. As well as a new brake cylinder, buy a set of brake shoes, they will almost certainly be contaminated. You should change all shoes on the back at the same time to maintain balance.
3. Buy some aerosols of brake cleaner - they will make short work of cleaning everything up.
4. Buy new brake fluid and a brake bleeding kit of some type, you will need to get the air out of the lines and cylinder.
5. You may struggle to get the brake shoe retaining pins off and get them back on again. You can buy a special tool to help but I use a pair of pliers.
6. Take some photos on your phone as you dismantle things. The arrangement of springs and shoes can be quite difficult to remember if you have a pile of parts in front of you!

Ian F
1972 BGT, Blaze, Navy trim, recessed grill
1961 Midget, 948cc, Clipper Blue, Blue trim and weather gear

Mario60
Posts: 45
Joined: Thu Jul 18, 2019 9:34 am
Forename: Mario
Surname: Sciriha
Location: Malta

Re: leak from the rear drum

Post by Mario60 » Thu Mar 26, 2020 8:32 am

Hi Ian,

Many thanks. I will inspect this afternoon when I am home and will let you know

Regards


Mario
Mario Sciriha
1972 MGB roadster
1971 MGB GT (for restoration)
1979 Honda CB650Z
1975 Kawasaki S1C 250
1974 Suzuki GT380
1979 Suzuki TS125

Ian Fozzard
Posts: 370
Joined: Fri Mar 27, 2015 8:18 am
Forename: Ian
Surname: Fozzard

Re: leak from the rear drum

Post by Ian Fozzard » Thu Mar 26, 2020 8:35 am

Very good Mario. Are you still able to travel where you are? Here in the UK we are asked not to go out, so our MGs are getting a lot of attention but little driving!!

Ian F
1972 BGT, Blaze, Navy trim, recessed grill
1961 Midget, 948cc, Clipper Blue, Blue trim and weather gear

Ian Fozzard
Posts: 370
Joined: Fri Mar 27, 2015 8:18 am
Forename: Ian
Surname: Fozzard

Re: leak from the rear drum

Post by Ian Fozzard » Thu Mar 26, 2020 8:54 am

http://www.geomatique-liege.be/MGJP/Doc ... Manual.pdf

Mario - I believe this link will give you a download of the original MGB workshop manual (pdf)

No guarantees of course, but it worked for me.

I could send you my downloaded copy, but it is a very large file - over 25mb.

Ian F
1972 BGT, Blaze, Navy trim, recessed grill
1961 Midget, 948cc, Clipper Blue, Blue trim and weather gear

Mario60
Posts: 45
Joined: Thu Jul 18, 2019 9:34 am
Forename: Mario
Surname: Sciriha
Location: Malta

Re: leak from the rear drum

Post by Mario60 » Thu Mar 26, 2020 9:11 am

Hi Ian

Here in Malta, we are not on a 100% lock down, we are still allowed to go out but not allowed. So we can still go for drives. With such a leak, can the B be driven until reparied

Thanks

Mario
Mario Sciriha
1972 MGB roadster
1971 MGB GT (for restoration)
1979 Honda CB650Z
1975 Kawasaki S1C 250
1974 Suzuki GT380
1979 Suzuki TS125

Mario60
Posts: 45
Joined: Thu Jul 18, 2019 9:34 am
Forename: Mario
Surname: Sciriha
Location: Malta

Re: leak from the rear drum

Post by Mario60 » Thu Mar 26, 2020 9:11 am

meant to say not allowed to be gathered in groups

sorry
Mario Sciriha
1972 MGB roadster
1971 MGB GT (for restoration)
1979 Honda CB650Z
1975 Kawasaki S1C 250
1974 Suzuki GT380
1979 Suzuki TS125

Ian Fozzard
Posts: 370
Joined: Fri Mar 27, 2015 8:18 am
Forename: Ian
Surname: Fozzard

Re: leak from the rear drum

Post by Ian Fozzard » Thu Mar 26, 2020 9:22 am

Mario, I would say don't drive it with a leaking brake system. It may be OK if only a slight leak, but it could fail in a big way, and of course your brake shoes may not be working very well if soaked in brake fluid or oil.

Ian F
1972 BGT, Blaze, Navy trim, recessed grill
1961 Midget, 948cc, Clipper Blue, Blue trim and weather gear

Mario60
Posts: 45
Joined: Thu Jul 18, 2019 9:34 am
Forename: Mario
Surname: Sciriha
Location: Malta

Re: leak from the rear drum

Post by Mario60 » Thu Mar 26, 2020 9:34 am

noted
Mario Sciriha
1972 MGB roadster
1971 MGB GT (for restoration)
1979 Honda CB650Z
1975 Kawasaki S1C 250
1974 Suzuki GT380
1979 Suzuki TS125

Mario60
Posts: 45
Joined: Thu Jul 18, 2019 9:34 am
Forename: Mario
Surname: Sciriha
Location: Malta

Re: leak from the rear drum

Post by Mario60 » Thu Mar 26, 2020 6:12 pm

Hi Ian.
Dismantled and ordered the parts. I have decided to refurbish both sides. I will keep you posted.
Thanks and regards
Mario
Mario Sciriha
1972 MGB roadster
1971 MGB GT (for restoration)
1979 Honda CB650Z
1975 Kawasaki S1C 250
1974 Suzuki GT380
1979 Suzuki TS125

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