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Brake Master Cylinder Part Numbers


AlexReed
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Hi All,

I am looking to get a replacement Brake Master cylinder for my triumph spitfire IV. When I bought the car it originally had a 0.75 inch bore diameter master cylinder fitted which worked very well and felt really nice to operate but unfortunately only had a small reservoir which was the same size as the clutch master cylinder which I wasn't happy with. Within the spares I got with the car there was a master cylinder which had a larger plastic reservoir (which I can see from restoration pictures I got with the car was the type fitted before it was restored) but only a bore diameter of 0.625 inches (standard spitfire IV size). I cleaned this up and fitted new seals to this master cylinder and fitted it to my spitfire. From then on I never found the brakes to be as responsive or as sharp as when I had the 0.75 master cylinder fitted. Now that the 0.625 master cylinder is leaking between the plastic reservoir and the ally main body I’m looking to get a replacement master cylinder but in 0.75 inch bore with the larger capacity reservoir. I've looked on the websites of all the usual suspects but they all seem to sell different ones and different GM part numbers (GM205, GM209, GM220, and GM224) but not all say the bore diameter size of them. 

Can anyone help locate the type of master cylinder I am looking for?

I have attached a photo with both of the master cylinders :)

Alex

IMG_5982.JPG

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have a browse at  https://www.carbuildersolutions.com/uk/master-cylinders

or places like merlin motor sport

i used a 0.7 with the plastic reservior ,   

going from 0.625 to 0.7 or0.75"  means the pedal travel will be less on the larger diameter but the pedal prssure has to be higher to get the same hydraulic ratio at the brakes 

the sizes change when larger diameter caliper pistos got introduced as there has to be som reserve in the travel/displacement

dont think  type 14 had a 0.7 but Vit  & gt6 with type 16 certainly went to the larger bore

land rover ones are cheap and often used for replacements 

Pete

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I had masses of trouble trying to source 0.75" master cylinder when I thought I had a problem. They are hen's teeth. Just had a look on Fleabay and this guy has some although the reservoir looks suspiciously small and he advertises as a brake/clutch MC replacement 

!https://www.ebay.co.uk/itm/MASTER-CYLINDER-Triumph-GT6-Clutch-Brake-UPRATED/390265236910?hash=item5add9eedae:g:uc8AAOxy4t1SeRxV

 

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50 minutes ago, Pete Lewis said:

have a browse at  https://www.carbuildersolutions.com/uk/master-cylinders

or places like merlin motor sport

i used a 0.7 with the plastic reservior ,   

going from 0.625 to 0.7 or0.75"  means the pedal travel will be less on the larger diameter but the pedal prssure has to be higher to get the same hydraulic ratio at the brakes 

the sizes change when larger diameter caliper pistos got introduced as there has to be som reserve in the travel/displacement

dont think  type 14 had a 0.7 but Vit  & gt6 with type 16 certainly went to the larger bore

land rover ones are cheap and often used for replacements 

Pete

Pete

i'm looking at the 0.75 bore from Car builder solutions https://www.carbuildersolutions.com/uk/075-brake-and-clutch-master-cylinder-without-reservoir

Am I correct in assuming that the plastic reservoir https://www.carbuildersolutions.com/uk/single-brake-fluid-reservoir-without-bracket-and-diaphragm would just screw into the master cylinder as they are both the 7/16 UNF fitting?

Also would the height of this reservoir on top of the master cylinder be to tall to fit under the bonnet height of the spitfire?

Alex

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Give David Kingerley of Classic Car Spares a call, he has excellent stock and much of it is NOS OE.

He will be at Stoneleigh on the 11th Feb; at which I am collecting a NOS B&B clutch kit from him.

Normally my first port of call on such enquiries.

Very nice chap and very helpful.

07977.914.088 (Mon - Sat, 9 to 6)

www.obsoletecarspares.co.uk

Regards.

Richard.

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Yes my existing one will fit on i have just cleaned it up and checked it over and it looks okay. I hadn't thought to put the original one on it so thanks for suggesting it. I'll order the 0.75 master cylinder from car builder solutions and see how that goes :)  

 

Alex

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Just and update:

I have fitted the new master cylinder as it arrived earlier in the week and wow it feels just like I remember the brakes feeling when I bought the car. I reused the original push rod and the plastic reservoir from the old master cylinder.

Thanks for everyone's help with this :)

Photo 02-02-2018, 3 22 15 pm_preview.jpeg

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Well done Alex, always great to have a satisfactory outcome.

A job for the future, will be to replace your R6 fuel hose for R9 which is the current hose to have dealing with Ethanol issues.

Regards.

Richard.

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Hello Alex.

I normally get my R9 hose from AFS, never had an issue to date and as their turnover is high the cost is decent.

Here is the link: https://www.advancedfluidsolutions.co.uk/76mm-id-516-saej30r9-nitrile-rubber-fuel-injection-hose-sae-r9-628-p.asp

Just click on the part number, that you need, at the bottom of the page and it will give you the correct hose price etc.

Regards.

Richard.

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