Brake Master Cylinder

[elanman999]

Kev,
The link (northwest classics) that Tim has given sell a re-build kit with seals, diaphragm etc. I re-built my servo a few months ago with their kit and it works well. It's on their site at ?70.
Cheers
John

[Wevster]

Thanks John

I?ll take a look. In a bit of a dilemma as I paid ?200 for it to be refub?d professionally by J+L who have been very helpful, and they will take it back under guarantee, still looking at ?40 delivery there and back, or buy a kit like you say for ?70 and have a go myself.
I need to do a bit more research.

Will let you know how it pans out.

Cheers for all your replies.

Kev.

[Wevster]

I've had a nice conversation with Peter at Northwest Classics who was very helpful and knowledgeable regards our servos.
He can also supply parts/seals internal parts for my particular servo etc, separately if required. I'll need to reinstall
my new m/c when it arrives and go from there.

Will report back next week with details.

Cheers

Kev

[Hawksfield]

Hi Wevster

I am sure your problem is in the servo with the control valve sticking when in use, I have had some experience when rebuilding the Girling MK11B servo which I have done on a number of times.
Beware people are supplying various size seals.
See the memo I wrote to myself after the last rebuild and by the way North West Classic has supplied seals too big although he replaced them.

Girling mk11B control piston seal sizes.doc

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[steveh]

Kev ,
I dismantled my servo a couple of days ago , i did a bit of searching around first on youtube and found this useful .The hardest part was removing the upper aluminium slug from the gummed up bore

https://www.youtube.com/watch?v=TJ-2KwQ8a94

Steve

[Wevster]

Thanks Hawksfield

That?s really helpful, I?ll check the sizes of the seals fitted to my servo, and compare sizes. My master cylinder has now arrived, however I?m away this weekend and will work on it next week.

Thanks for your info.

Cheers

Kev.

[Wevster]

Thanks Steve

Quite comical, definitely shows some of the pitfalls when dismantling!
Update so far, re installed the new m/c last night, bleed through and fired up, applied brakes and they locked up again, so definitely the servo. Will be on it next week.

Cheers

Kev.

[alan.barker]

Have you tried, remove in and out pipe on servo and connect the 2 together with a double female adapter.
Bleed system and test again.
Alan
sorry i have just seen have done this already

[Wevster]

Hi Wevster

I am sure your problem is in the servo with the control valve sticking when in use, I have had some experience when rebuilding the Girling MK11B servo which I have done on a number of times.
Beware people are supplying various size seals.
See the memo I wrote to myself after the last rebuild and by the way North West Classic has supplied seals too big although he replaced them.

Girling mk11B control piston seal sizes.doc

Hi Hawksfield

I've now carefully dismantled my servo and have measured the seals, my seals are still on the piston and its very difficult to measure accurately to the nearest 100th of a mil. however it appears that primary seal is around 16.39mm and secondary 9.74mm. So if I can obtain 16.01 & 9.64 as you have fitted it maybe the answer.
What about the seals on the output piston?
I've also noticed that according to the Girling exploded drawing, number 19 (piston stop) is missing from my servo, could this also be a contributing factor?
When you re-assembled your servo, did you use grease or just fresh fluid as described in Repair Procedure Instructions?
Many thanks for your help

Cheers

Kev.

[Hawksfield]

Hi Webster
I measured the pilot seals off the piston using a vernier gauge adjusting till it could just be held between the gauge faces.
The other seals are not problem for locking brakes as the spring return is quite strong.
As you see from my sizes having both seals over size can make the pilot piston stick, I could tell when compared each seal fitted by Han movement.

The only grease I used was rubber grease on the large piston rod
The stop end is not always fitted to some servos in the girling document it says (if fitted)

Good luck

[Wevster]

Hi All and Season Greetings

Update on proceedings so far, I had a problem with the threaded part on the hydraulic body of the servo. The bolts that secure it to the bracket were incorrect and had a shank on them, thus when i'd tighten them up they had cracked both bottom lugs.(silly mistake on my part). These have now been repaired and the servo has been rebuilt.
As my servo had been rebuilt not that long ago all parts were serviceable. It was only the seals for the control piston that i'd like to have changed. These weren't as easy to obtain as i'd first thought so in the end I've reused the originals and will keep an eye on it, but so far so good. I did use some silicon grease on rebuild but only sparingly making sure everything was moving correctly, and then filled each cylinder with fluid before final construction.
I bleed from the new master cylinder directly to the servo first, bleeding through inlet to the outlet, before commencing with the rest of the system, I used the old fashion 'Misses on the pedal' method. This took quite a while, a good book, a litre of fluid and me going around the car many time shouting "up" down" ... you all know the story.
The brakes now work, with no locking up. There's quite a bit of travel on the pedal, however the front pads aren't great and the front right wheel bearings need changing.
Better get on with it!

Happy New Year

Kev.

[Hawksfield]

Hi Kev

Did you by chance measure the seals you installed as I would like to know the dimensions of the original Girling piston seals. I would like to get hold of some new old seals to establish a standard

Hope you have solved the problem
Merry Xmas

[Wevster]

Hi Hawksfield
The measurements of the seals I re-used were 9.74 secondary and 16.39 primary. Which I know is still on the large side compared to yours.
Unfortunately I didn?t see the originals seals that these replaced. I agree it would be helpful if there was a standard size as I didn?t realise kits came with different size seals. Where did you get yours from? Just in case I need some in the future.

Cheers

Kev.

[Hawksfield]

Wevster

Will get together the info for you

All the best

[Hawksfield]

Hi Kev

I have had seals from two suppliers Northwest Classic twice and Automobileelectrics once.

The second supply from NWC the secondary seal was too big and eventually NWC agreed and sent me a replacement after I sent an old used sample.
I was still having problems occasionally of slow brake release and I investigated further and found that the control piston primary was suspect.
I noticed Automobileelectrics on ebay were selling sets of seals for the Girling MK11B, which I purchased,
These seals were the largest of the control pistons seals I received.
At this point I decided to measure all the seals I had in my possession and fit the smallest after an assessment fitting and testing by hand. The servo has been fine now for since April this year
After this long winded problem I now check and measure everything I can and take photo's because lots of spare parts are remanufactured for our cars.

Just noticed a new supplier of seals https://www.ebay.co.uk/itm/Ford-Lotus-C ... 1438.l2649

They might be better sizes but the seller tells me they are manufactured to Girling spec.

New message from: slate-hall Top Rated Seller(2,190Red Star)

Hi, no these seals are not genuine Girling, you will find that in most cases original new old stock Girling and Lockheed seals shrink and go hard with age and that is why these seals are remanufactured to the original Girling specification, kind regards Andy.

Girling mk11B control piston seal sizes.doc

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Kev you get what you can today good luck