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Clutch master cylinder differences


66gaza
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I asked a similar Q on the international section but drew a blank, hoping this is the place with the answers. The series clutch masters are listed as CB compression barrel and CV don't know what this stands for yet (anyone?) On a website I was on it listed SWB as 7/8" bore and 1.125" for some of the LWB types these are single circuit. But when I went to a local motor factors they had a CB type one but was only 3/4", can someone shed some light on this. I expect the 3/4" master would have worked but I am wanting to use it in another application.

Gaza

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You must mean brake master, not clutch. The larger bore is for the 109's because they have 2 slaves per front wheel, so need more fluid. I think the CB was a pain in the butt to bleed all the air out of unless you did it before installing it. What is the application you are using the master on?

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You must mean brake master, not clutch. The larger bore is for the 109's because they have 2 slaves per front wheel, so need more fluid. I think the CB was a pain in the butt to bleed all the air out of unless you did it before installing it. What is the application you are using the master on?

Hi Jimfoo, yes I did mean brake, I said clutch because that is the application I want to use it for. My 3/4" master in my defender now doesn't push enough fluid to move the new slave in my application. The new slave is 1" bore. So I am looking for a bigger master and the series with single circuit brakes looked like a good bet.

Gaza

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Hello,

FWIW, I am not an expert on LR's, I have a 79', swb, single circuit, no servo. When I bought it it had a brake m/c with a seperate tank for the fluid. Do not remember the parts number, but the bore was only 5/8". I now have the same type master cylinder on both brake and clutch, it is the clutch m/c parts number: 550732, it has a 3/4" bore. It was an improvement over the old brake m/c, but will not help you much if you are lookin for a 1 1/8" bore. I think my brake wheel cylinders were 1" rear and 1 1/8" on the front.

Sorry can' t be of more help.

Master cylinder # 550732 brake and clutch.

post-208-1192037146_thumb.jpg

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Hello,

FWIW, I am not an expert on LR's, I have a 79', swb, single circuit, no servo. When I bought it it had a brake m/c with a seperate tank for the fluid. Do not remember the parts number, but the bore was only 5/8". I now have the same type master cylinder on both brake and clutch, it is the clutch m/c parts number: 550732, it has a 3/4" bore. It was an improvement over the old brake m/c, but will not help you much if you are lookin for a 1 1/8" bore. I think my brake wheel cylinders were 1" rear and 1 1/8" on the front.

Sorry can' t be of more help.

Master cylinder # 550732 brake and clutch.

post-208-1192037146_thumb.jpg

Hi, thanks for the reply it would be good to have both the same so spares are common. I might get away with a 7/8" it must be larger than 3/4" after that I might have to suck it and see.

Gaza

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which slave are you using at the moment?

is it not easier to get a lr slave in there somehow?

Hi Tonk, I am desperatly trying to use a rover master cylinder. Currently have a standard Defender 3/4" one but it doesn't move enough fluid to operate my new 1" slave so I am looking at other rover master cylinders, hence my Q.

Gaza

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so u cant get a smaller pistoned slave in there?

i realise that would make the clutch heavier to use but its just a different way of lookin at the problem ;)

My new engine uses a 13" clutch so possibly needs the 1" slave. AFAIK some series vehicles used a 7/8" brake master so thats why i am asking.

Gaza

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Thanks for the replies. this site http://www.rovahfarm.com/series.htm lists the series brake masters and there sizes. The one at the top Ref: 520849 is listed there as 7/8" but at a motorfactors yesterday he got one out for me and it had 3/4" cast into it. What I would like to know is if I order Ref: 90569126 7/8" CV type from paddocks for instance will it come as 7/8" as the US site lists it as or will it be smaller 3/4" like my experience with the local motor factors. Has anyone bought one recently and can confirm it is 7/8" in the uk?. there is also a 1.125" (1 1/8") size item 90569128G. Also has anyone bought the non Lucas items and found them OK?

Gaza

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The LWB S2A/S3A single cct non servo I bought is 1" bore (P/N 90569128) but on the above site it is supposed to be 1.1/8". Has anyone bought a CV type lately and can cofirm sizes, are the Lucas ones the same size as the non branded ones? BTW it fits and operates my clutch OK but is a little heavy so the 7/8" would probably be better. Is a Lucas 90569126 3/4" or 7/8" bore? Thanks

Gaza

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Looking at dingocroft

http://shop.dingocroft.co.uk/acatalog/Hydraulics.html

I see a master cylinder with the following specification:

Replacement Brake Master Cylinder S2A & S3 Ref: 90569128D

Application: 109" non-servo vehicles 'CV' type cylinder.

Description: Replacement single line brake master cylinder for use with remote reservoir.

Approximate dimensions: Length excluding pushrod 143mm (5.63"), bore 28.6mm (1.125"), mounting hole centres 63.5mm (2.5").

Price: £16.00£18.80 (Including: VAT at 17.5%)

Any good?

Never used Dingocroft but never heard anything bad either.

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Looking at dingocroft

http://shop.dingocroft.co.uk/acatalog/Hydraulics.html

I see a master cylinder with the following specification:

Replacement Brake Master Cylinder S2A & S3 Ref: 90569128D

Application: 109" non-servo vehicles 'CV' type cylinder.

Description: Replacement single line brake master cylinder for use with remote reservoir.

Approximate dimensions: Length excluding pushrod 143mm (5.63"), bore 28.6mm (1.125"), mounting hole centres 63.5mm (2.5").

Price: £16.00£18.80 (Including: VAT at 17.5%)

Any good?

Never used Dingocroft but never heard anything bad either.

Thanks for the reply, this is the problem though what they are supposed to be and what they are is not the same. I have just bought the exact same master cylinder as you have pointed out yet it is not 1.125" but 1" exactly or the 1 cast into it is confusing me. I did look at a CB SWB which is supposed to be 7/8" but had 3/4" cast into it, so they were both 1/8" smaller than they were supposed to be, go figure.

Gaza

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um, tricky.

I wonder if the same principle has applied to the slave - sold as 1" but cast as 7/8" ???

Some out of box thinking here - could you use a Dual circuit master cylinder with both outputs plumbed into the slave input using a Tee piece?

Other than that you are looking at getting the 1" bored and slieved to your spec (non standard - yeuch!). There are a few outfits that do this for the classic car market - isn't cheap though.

I'd try the 1" and see how bad it was, I am also led to believe the td5 defender clutch pedal has extra assistance by way of a helper spring, perhaps you could mimic this?

best of luck, and do post your eventual solution - share the pain.

G.

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