Series 3 Master Brake cylinder

Mark Frewin · Apr 30, 2018

Hi
Overhauling the brakes on a 1979 SWB series 3 with Servo and dual line master cylinder. I have purchased a new master cylinder and have been sold a Bearmach BR0726 90577520 which looks identical to the one fitted but on removal the old one is a 3/4" bore and the new BR0726 is an 1" bore. will it be ok to fit or must l have the smaller bore. (the 1" unit mechanically fits)) Your advice greatly apprieciated
Mark

rob1miles · Apr 30, 2018

That's a signficant differnce. The new one is a little over 1/2 the area of the orignal (3/4 x 3/4 = 9/16) which means the pedal force will be close on double. Do you know what the correct dia is for your set up with a servo?

Citizen Kane · Apr 30, 2018

If you have TLS fronts the master cylinder usually carries the cast in number 64677249, if you have SLS fronts then the master cylinder usually carries the number 64676942.

Mark Frewin · Apr 30, 2018

Hi Sorry for delay just back from work. The vehicle has SLS on front and rear, there are no numbers on the old cylinder but I have measured the bore at 21.5mm approx.The new cylinder measures through the sealed plastic bag at 24.5mm so only roughly 3mm bigger. I was quoting before measurements from the Haynes manual which are SWB 19mm and LWB 25mm?. According to the Land Rover Parts Catalogue the same servo is fitted to both SWB and LWB. The Servo is shot by the way and l am fitting a new one as well. The vehicle has had 12 owners in its life so I don't even know if the old cylinder was the correct part. I hope this info may help and many thanks for both your inputs so far.
Mark

Citizen Kane · Apr 30, 2018

There are a few visible cues, have a look here http://www.expeditionlandrover.info/dual_brake_conv.htm

You need the smaller bore cylinder for SLS

jamesmartin · Apr 30, 2018

Mark Frewin said:
Hi Sorry for delay just back from work. The vehicle has SLS on front and rear, there are no numbers on the old cylinder but I have measured the bore at 21.5mm approx.The new cylinder measures through the sealed plastic bag at 24.5mm so only roughly 3mm bigger. I was quoting before measurements from the Haynes manual which are SWB 19mm and LWB 25mm?. According to the Land Rover Parts Catalogue the same servo is fitted to both SWB and LWB. The Servo is shot by the way and l am fitting a new one as well. The vehicle has had 12 owners in its life so I don't even know if the old cylinder was the correct part. I hope this info may help and many thanks for both your inputs so far.
Mark

what m/c did you order ,has it 2 pipe connectors or 1

Mark Frewin · Apr 30, 2018

Hi It has 2 pipe connnections

Series 3 Master Brake cylinder

Mark Frewin

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rob1miles

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Citizen Kane

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Mark Frewin

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Citizen Kane

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jamesmartin

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Mark Frewin

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