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Brake fluid leak and washers

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Brake fluid leak and washers
#1
GB3 George B
Winter Haven, USA   USA
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I had a brake fluid leak at both banjo fittings on a front wheel after doing brake job on the TD. New cylinders, washers, hose, and the plain banjo bolt, no clue why leaking. . In frustration, I ordered another set of washers , banjo bolt and adaptor. All mating surfaces were perfect on the banjos and the cylinders. Look at the smaller OD washer- there is only a tiny rim of the washer that was sealing (the inner part is raised, the outer compressed). Note how much bigger OD the other washer is. The sealing area is vastly larger than with the small washer. Totally dry overnight for the first time. I have a large collection of copper washers from many suppliers, no clue where the small one came from. The larger one is new in kit from Moss. So make sure you have one of the larger OD copper washers like on the left in the picture or you may have leaks. George


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Re: Brake fluid leak and washers
#2
Mervo Merv Hyde
Peregian Beach, Queensland, Australia   AUS
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George I have just finished this same task (other thread). I kept all the old copper washers, but also ordered new ones. There were 2 ID sizes needed - 3/8" and 7/16". They also seemed to be a bit thinner than the ones I took off. I decided to reuse the existing ones and spent some time carefully flattening them off to get a level surface. Especially the ones on the adapter and banjo connector. No leaks so far, under pressure and when driving.


Merv Hyde
Queensland Australia
MG TF 1500
Porsche 356B (S) 1962
Porsche 911 Carrera 1988

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Re: Brake fluid leak and washers
#3
Tpss Avatar
Tpss Tim Parrott
Stroud, gloucestershire, UK   GBR
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1938 MG TA
You need to anneal used washers to soften them. Heat them with a gas blow torch and then leave them to cool. They harden once used so no good for a second time around in their current state!

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Re: Brake fluid leak and washers
#4
AbingdonNerd Gold Member Jeffrey Delk
Hartwell, GA, USA   USA
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1950 MG TD
I have just been through this on one TD, and have another with the same issue.

I am convinced that the material used for the “copper” washers has been changed. The washers are much harder than they used to be. Several individuals commented that this change may have been prompted by the price of copper.

I did a Google search about leaking copper brake washers - and there are many posts on varied car enthusiast sites, each have this same problem. Another concern is that the stamping process may be distorting the washers - and this, along with the harder alloy, may be compounding the problem.


Jeffrey W. Delk
Hartwell. Georgia USA
1950 MGTD #2301
1954 MGTF 1500 #7673
1957 MGA
1971 MGB Tourer

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Re: Brake fluid leak and washers
#5
Tpss Avatar
Tpss Tim Parrott
Stroud, gloucestershire, UK   GBR
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1938 MG TA
I should have added that you need to anneal new washers as well as they are “work hardened” by the manufacturing process!

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Re: Brake fluid leak and washers
#6
plus4moggie Tom Lange
Bar Harbor, ME, USA   USA
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I have always done one more thing I learned from an old-time Ford mechanic, that has increased the amount I safely tighten a brake banjo fitting. Once I have tightened the banjo down all that I feel comfortable, I give the head of the bolt a rap with a hammer. I re-tighten the bolt, and repeat three or four times, and almost always find that I can tighten the fitting a bit more each time. I'm not suire why, but it works!

Tom Lange
MGT Repair

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Re: Brake fluid leak and washers
#7
wiia WILLIAM ADAMS
Terre Haute, IN, USA   USA
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1955 MG TF 1500
1961 MG MGA 1600
For what it's worth Harbor Freight Tools sells an 80 piece copper washer assortment for US$7. https://www.harborfreight.com/80-piece-copper-washer-assortment-67526.html


Bill

1961 MGA
1955 MG TF-1500
1954 Chevrolet 3100

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about 1 week and 22 hours later...
Re: Brake fluid leak and washers
#8
Fsisson Avatar
Fsisson fred sisson
nashville, IN, USA   USA
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1938 Morgan 3 Wheeler
1950 MG TD "Second Hand Rose"
1952 MG TD MkII "The Black MG"
1990 Mazda MX-5
Dowdy washers and done. But if you use copper, always (always!) anneal, even (especially) when new. New washers are already simi-hard just from being stamped out. Gotta be soft to work. They work- harden as soon as you tighten them. When annealed you can feel 'em squish and seal.
Lay them on the vise, heat them with a propane torch to bright red/yellow. Cool 'em anyway you want... not at all critical. Takes a couple of minutes. Now you have a soft copper washer.


Old and opinionated car nut since a child. Owned and DRIVEN over 125 cars from 2Isettas, 3XK140 & 1EtypeJags, 3SAAB 96+ 97 and Sonett, 3Porsche356 +356A Carrara 1500GS & 914-6, 170 219 220 Mercedes +300SL roadster, 289 '64Cobra, Nash, 8MGs, 2Model A's 2Crosleys, Cord 810, International, Jeep, 5VWs, Renault, Morgan 3&4 wheels, 3NAMiatas+V8, etc. Twitterpated bad since young.

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Re: Brake fluid leak and washers
#9
Mervo Merv Hyde
Peregian Beach, Queensland, Australia   AUS
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I fully agree on the annealing and also Tom’s suggested hammer � impacts on final tightening. I had one reluctant fitting (as usual the last one) with a slight weep of fluid. These approaches both helped.


Merv Hyde
Queensland Australia
MG TF 1500
Porsche 356B (S) 1962
Porsche 911 Carrera 1988

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Re: Brake fluid leak and washers
#10
Mikelead Avatar
Mikelead Mike Leadbeater
York, Yorks, UK   GBR
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1953 MG TD
thumbs up for Fred, I fixed my dripping banjo on the master cylinder, after several attempts, anealing, aluminium etc, without success, by fitting a Dowty washer, job sorted. Bought an assortment on ebay.

Mike

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Re: Brake fluid leak and washers
#11
AbingdonNerd Gold Member Jeffrey Delk
Hartwell, GA, USA   USA
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1950 MG TD
I am tackling leaking washers on another complete TD job this morning just heated up the new washer set cherry red - will be replacing most of the new washers that were used last week when rebuilding the system - fingers crossed.

My overriding reaction to all of this is - “This was never a problem before”

So, a change must have been made to the copper alloy being used.

Even the most basic repairs have become a real pain. I would pay $30 for a set of proper copper washers - if necessary- to avoid the hassle of the leaking joints.


Jeffrey W. Delk
Hartwell. Georgia USA
1950 MGTD #2301
1954 MGTF 1500 #7673
1957 MGA
1971 MGB Tourer

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Re: Brake fluid leak and washers
#12
GB3 George B
Winter Haven, USA   USA
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I agree. Most likely the sealing surfaces of the new cylinders are not so great, And I know a couple of my original banjo bolts were really messed up. To follow up on Tom's post, when I seat dental implant abutments, I always vigorously tap on them a couple times and re-torque each time. There is almost always a little bit more tightening movement. George

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Re: Brake fluid leak and washers
#13
wiia WILLIAM ADAMS
Terre Haute, IN, USA   USA
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1955 MG TF 1500
1961 MG MGA 1600
With respect t Dowty washers, I didn't know what they were and looked them up. Dowty washers are washers with a bonded seal in the ID. The sealing material may be a rubber or polymer compound. The Dowty washers I looked at had resistance to petroleum-based fluids and water. However, brake fluid is a polyglycol fluid with anti-corrosion additives. Dot 4 has a higher boiling point than Dot 3. Dot 5 is silicone based and incompatible with Dot 3 and DOT 4.

A note of caution. If using Dowty washers in the brake system, be certain that the sealing material is resistant to brake fluid. Otherwise future leakage may occur if the sealing materials is chemically deteriorated by contact with brake fluid.


Bill

1961 MGA
1955 MG TF-1500
1954 Chevrolet 3100

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Re: Brake fluid leak and washers
#14
Tpss Avatar
Tpss Tim Parrott
Stroud, gloucestershire, UK   GBR
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1938 MG TA
We used Dowty Washers in Aircraft Hydraulic systems. My assumption without any clear supporting evidence is that they are resistant to Hydraulic fluid. I have used one in my brake system with Dot4 fluid with no issue.

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Re: Brake fluid leak and washers
#15
Declan Burns Avatar
Declan Burns
Duesseldorf, NRW, Germany   DEU
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1952 MG TD
1964 Morris Minor 1000 Tourer "Moggy"
William,
You are quite right! Make sure you use dowty washers with EPDM rubber which is resistant to brake fluid. Goodridge make their so called "Stat-O-seals" which is what I use. It is a bonded aluminium crush seal washer for braking systems although I don't find a specification for the rubber on their website.
They are quite expensive as opposed to standard NBR dowty washers but I can supply them at just over half the price.
Regards
Declan



Edited 1 time(s). Last edit at 2024-04-29 10:55 AM by Declan Burns.

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