Tandem brake master cylinder

[new to this]

Im upgrading my single master cylinder to a Tandem one,what size thread are they for the brake pipes,the inner one nearest the servo is 3/8 its the outer one i dont know,its not 7/16 or 10mm

they for any help Dave

[Carledo]

It's a 12mm metric thread. It's the same as used on some french cars into the rear wheel cylinders, notably Peugeot.

If you need one, I have some in stock!

Cheers Steve

PS the one nearest the servo should be a 10mm short metric, it has been on all the dual circuit cylinders i've had!

[new to this]

It's a 12mm metric thread. It's the same as used on some french cars into the rear wheel cylinders, notably Peugeot.

If you need one, I have some in stock!

Cheers Steve

PS the one nearest the servo should be a 10mm short metric, it has been on all the dual circuit cylinders i've had!

Steve

thanks for help, i didnt think BL would have used metric,the nearest one by the servo i tiried 3/8 that fitted but ill check if 10mm fits,the only one i didnt have was 12mm,ill order one,im at the stage now of making up the brake lines and will run new fuel lines at the same time

thanks Dave

[Carledo]

The pipes and unions on the dual circuit cars are a real mishmash of fittings. The front pipe from the M/Cyl (front brake circuit) is 12mm at the cylinder and 7/16" UNF at the PDWA (if fitted) and the rear pipe, nearest servo and feeding the rear brakes is 10mm at the M/cyl and 3/8" UNF at the PDWA.

If you are ditching the PDWA (recommended by me) then the unions you use will be whatever fits the 3 way and inline joiners you buy to replace the PDWA. It's easy to do if you are starting from scratch.

If you don't want to guess and hope or approximate the pipe lengths, I can give you exact numbers from factory pipes as a cutting list. The lengths I provide (and use myself when supplying pipes) include an extra 4mm to allow for the shortening effect of flaring the ends. Yes I AM that anal about it!

Don't forget that this dual circuit cylinder did not appear on UK cars until the tail end of 1978 when metrication was in full flow. It's not the same cylinder as was used on export cars from 73> and which (ironically, in view of its destination markets) WAS all imperial in it's fittings!

Steve

[new to this]

The pipes and unions on the dual circuit cars are a real mishmash of fittings. The front pipe from the M/Cyl (front brake circuit) is 12mm at the cylinder and 7/16" UNF at the PDWA (if fitted) and the rear pipe, nearest servo and feeding the rear brakes is 10mm at the M/cyl and 3/8" UNF at the PDWA.

If you are ditching the PDWA (recommended by me) then the unions you use will be whatever fits the 3 way and inline joiners you buy to replace the PDWA. It's easy to do if you are starting from scratch.

If you don't want to guess and hope or approximate the pipe lengths, I can give you exact numbers from factory pipes as a cutting list. The lengths I provide (and use myself when supplying pipes) include an extra 4mm to allow for the shortening effect of flaring the ends. Yes I AM that anal about it!

Don't forget that this dual circuit cylinder did not appear on UK cars until the tail end of 1978 when metrication was in full flow. It's not the same cylinder as was used on export cars from 73> and which (ironically, in view of its destination markets) WAS all imperial in it's fittings!

Steve

Steve

The PDWA valve i was going to use had seized,so been cleaning it now have it moving again,if you have pipe lengths that would save me running under the car with bits of string

Out of all the pipe fittings 12mm is the dearest

Dave

[Carledo]

The pipes and unions on the dual circuit cars are a real mishmash of fittings. The front pipe from the M/Cyl (front brake circuit) is 12mm at the cylinder and 7/16" UNF at the PDWA (if fitted) and the rear pipe, nearest servo and feeding the rear brakes is 10mm at the M/cyl and 3/8" UNF at the PDWA.

If you are ditching the PDWA (recommended by me) then the unions you use will be whatever fits the 3 way and inline joiners you buy to replace the PDWA. It's easy to do if you are starting from scratch.

If you don't want to guess and hope or approximate the pipe lengths, I can give you exact numbers from factory pipes as a cutting list. The lengths I provide (and use myself when supplying pipes) include an extra 4mm to allow for the shortening effect of flaring the ends. Yes I AM that anal about it!

Don't forget that this dual circuit cylinder did not appear on UK cars until the tail end of 1978 when metrication was in full flow. It's not the same cylinder as was used on export cars from 73> and which (ironically, in view of its destination markets) WAS all imperial in it's fittings!

Steve

Steve

The PDWA valve i was going to use had seized,so been cleaning it now have it moving again,if you have pipe lengths that would save me running under the car with bits of string

Out of all the pipe fittings 12mm is the dearest

Dave

The ones I had real trouble finding were the most expensive, those are the 3x7/16" UNF 3/16" bore males for the front circuit in the PDWA! You can get the 12mm male from any motor factors, I could only find the 7/16" males at one UK supplier at around £1.50 each! My factors don't even list them!

I'll PM you a list of the pipe lengths and their correct fittings, tailored to your car, one quick question, are you keeping or deleting the rear LSV? This affects the rear section of the front to rear pipe! Since the LSV is nearly always seized solid, I have a habit of deleting it especially on TJ equipped cars which no longer need it! I also have a spare NON LSV Goodridge rear flexi hose if you need that. I may even be able to find a good used hanger bracket for it!

Steve

[xvivalve]

I told you Steve would know!

[new to this]

The pipes and unions on the dual circuit cars are a real mishmash of fittings. The front pipe from the M/Cyl (front brake circuit) is 12mm at the cylinder and 7/16" UNF at the PDWA (if fitted) and the rear pipe, nearest servo and feeding the rear brakes is 10mm at the M/cyl and 3/8" UNF at the PDWA.

If you are ditching the PDWA (recommended by me) then the unions you use will be whatever fits the 3 way and inline joiners you buy to replace the PDWA. It's easy to do if you are starting from scratch.

If you don't want to guess and hope or approximate the pipe lengths, I can give you exact numbers from factory pipes as a cutting list. The lengths I provide (and use myself when supplying pipes) include an extra 4mm to allow for the shortening effect of flaring the ends. Yes I AM that anal about it!

Don't forget that this dual circuit cylinder did not appear on UK cars until the tail end of 1978 when metrication was in full flow. It's not the same cylinder as was used on export cars from 73> and which (ironically, in view of its destination markets) WAS all imperial in it's fittings!

Steve

Steve

The PDWA valve i was going to use had seized,so been cleaning it now have it moving again,if you have pipe lengths that would save me running under the car with bits of string

Out of all the pipe fittings 12mm is the dearest

Dave

The ones I had real trouble finding were the most expensive, those are the 3x7/16" UNF 3/16" bore males for the front circuit in the PDWA! You can get the 12mm male from any motor factors, I could only find the 7/16" males at one UK supplier at around £1.50 each! My factors don't even list them!

I'll PM you a list of the pipe lengths and their correct fittings, tailored to your car, one quick question, are you keeping or deleting the rear LSV? This affects the rear section of the front to rear pipe! Since the LSV is nearly always seized solid, I have a habit of deleting it especially on TJ equipped cars which no longer need it! I also have a spare NON LSV Goodridge rear flexi hose if you need that. I may even be able to find a good used hanger bracket for it!

Steve

Steve

I think i may have spare 7/16 unf male pipe fittings,Yes im am taking the LSV out, mine is seized,together with the TJ front brakes im also fitting rear disc brakes ive just got to sort out the hand brake cable and do the pipe work,on my car some one had cut and fitted a join in the rear pipe run

Dave

[Carledo]

There is a factory join in the front to rear pipe, just ahead of the handbrake lever. It has female pipe unions and a double male joiner in the middle. You CAN leave this out if you want and make a single front to back pipe. In such case add 10mm to the combined lengths of the 2 front to back pipes I give you.

The Sprint rear flexi hose is different to the non Sprint one (no LSV) So if you are leaving the LSV off you will need the different flexi and a front support bracket for it. (The holes for this bracket, with captive nuts, will be in the floorpan, forward and inboard of the LSV bracket fitting)

Steve

[new to this]

There is a factory join in the front to rear pipe, just ahead of the handbrake lever. It has female pipe unions and a double male joiner in the middle. You CAN leave this out if you want and make a single front to back pipe. In such case add 10mm to the combined lengths of the 2 front to back pipes I give you.

The Sprint rear flexi hose is different to the non Sprint one (no LSV) So if you are leaving the LSV off you will need the different flexi and a front support bracket for it. (The holes for this bracket, with captive nuts, will be in the floorpan, forward and inboard of the LSV bracket fitting)

Steve

Steve

ive just made a plate that fits over the original; LSV pick up points,and fitted a 3 way union to that then i can pick up the rear calipers

Dave

[Carledo]

There is a factory join in the front to rear pipe, just ahead of the handbrake lever. It has female pipe unions and a double male joiner in the middle. You CAN leave this out if you want and make a single front to back pipe. In such case add 10mm to the combined lengths of the 2 front to back pipes I give you.

The Sprint rear flexi hose is different to the non Sprint one (no LSV) So if you are leaving the LSV off you will need the different flexi and a front support bracket for it. (The holes for this bracket, with captive nuts, will be in the floorpan, forward and inboard of the LSV bracket fitting)

Steve

Steve

ive just made a plate that fits over the original; LSV pick up points,and fitted a 3 way union to that then i can pick up the rear calipers

Dave

Thanks for that! That complicates matters and alters lengths and fittings i've just sent you! Don't open the PM yet, i'll edit it!

[Carledo]

OK, PM edited and resent!

Steve

[new to this]

OK, PM edited and resent!

Steve

Steve

Thanks have got all the right size pipe unions now ,after a couple of try runs got some made (had forgotten how to use the flaring tool ) could that be old age

Dave