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Rear Brake Cylinders

PostPosted: Sat Aug 12, 2023 2:30 pm
by Andrew Morris
]Hi there,can anyone assist please. My late HC has the lockheed self adjusting brake facility and i have needed to replace the N/S rear wheel cylinder. All successful until i came to re connect the brake lines but discovered the bore on the cylinder is too small to allow the brass fitting to fit. The 2 apertures on the cylinder, fluid in and fluid out to o/s are both different sizes as the brake pipe will only fit one thread. :(

Im guessing the cylinders are different on both N/S and O/S on the later models.

Any help greatly appreciated, Thanks

Re: Rear Brake Cylinders

PostPosted: Sat Aug 12, 2023 6:07 pm
by droopsnoot
Interesting - both of mine (HPF and Sportshatch) have the same cylinders on both sides - the only difference is that the nearside one has the pipe in and pipe out, and the offside has the pipe in and the bleed nipple. As I've put new cylinders on both, though, that doesn't mean they would originally have been the same.

The parts book does list different cylinders for NS and OS on the OHV-engined cars, it also lists different cylinders for each side on UK OHC-engined cars, but lists the same one for both sides as the NLS replacement.

Would it just be easiest to put a different union on the end of the pipe?

Re: Rear Brake Cylinders

PostPosted: Sat Aug 12, 2023 6:23 pm
by Andrew Morris
droopsnoot wrote:Interesting - both of mine (HPF and Sportshatch) have the same cylinders on both sides - the only difference is that the nearside one has the pipe in and pipe out, and the offside has the pipe in and the bleed nipple. As I've put new cylinders on both, though, that doesn't mean they would originally have been the same.

The parts book does list different cylinders for NS and OS on the OHV-engined cars, it also lists different cylinders for each side on UK OHC-engined cars, but lists the same one for both sides as the NLS replacement.

Would it just be easiest to put a different union on the end of the pipe?


Thanks for this, your absolutley bang on ,mine is exactly as you describe ,line in, line out but line out is where the bleed nipple is and of course the bore is much smaller. Dont suppose anyone knows whether a bleed nipple sized thread is available to fit the standard sized brake pipe.

Appreciate your reply, real head scratcher this one.

Dont suppose you have the reference codes for the N/S AND O/S brake cylinders for the OHV models from the parts book ?

Re: Rear Brake Cylinders

PostPosted: Sat Aug 12, 2023 7:21 pm
by droopsnoot
Rear brakes, Lockheed, CX10100-CX219999, CY101001-CY199999:

Cylinder Assy RH: 2680850 - NLS, use 91023202
Cylinder Assy LH: 2680851 - NLS, use 91023203

DX100001-FX199999, DY100001-EY120847

Cylinder Assy RH: 9961646 - NLS, use 91041130
Cylinder Assy LH: 9961647 - NLS, use 91041181

Interestingly both of these list the bleed nipple as being the same, 6353493. It also lists five different flare nuts for the various brake pipes, one 3/16", three 3/8"-24tpi, and one M10x1 (which is almost certainly the master cylinder end of the pipes). There are too many combinations to list, if you want to send me your VIN I might be able to see which fittings should be on the car, but we all know that VM used whatever was to hand on the production line.

As for whether the different fitting is available, you'd need to measure it to confirm the size and then have a look - there are lots of different sizes, most widely available.

Re: Rear Brake Cylinders

PostPosted: Sat Aug 12, 2023 8:01 pm
by Andrew Morris
droopsnoot wrote:Rear brakes, Lockheed, CX10100-CX219999, CY101001-CY199999:

Cylinder Assy RH: 2680850 - NLS, use 91023202
Cylinder Assy LH: 2680851 - NLS, use 91023203

DX100001-FX199999, DY100001-EY120847

Cylinder Assy RH: 9961646 - NLS, use 91041130
Cylinder Assy LH: 9961647 - NLS, use 91041181

Interestingly both of these list the bleed nipple as being the same, 6353493. It also lists five different flare nuts for the various brake pipes, one 3/16", three 3/8"-24tpi, and one M10x1 (which is almost certainly the master cylinder end of the pipes). There are too many combinations to list, if you want to send me your VIN I might be able to see which fittings should be on the car, but we all know that VM used whatever was to hand on the production line.

As for whether the different fitting is available, you'd need to measure it to confirm the size and then have a look - there are lots of different sizes, most widely available.


Thanks Mike will have a look

Re: Rear Brake Cylinders

PostPosted: Thu Aug 17, 2023 6:13 am
by StefanM
Correct cylinders for 1256 74-79 self adjusting lockheeds are as follows:
RH 91041130, 4242-626, LW11626, 19mm and 1/4-3/8" ports, flat slotted piston.
LH 91041181, 4241-378, LW11378, 19mm and 3/8-3/8" ports, flat slotted piston.

So they all just have the 1/4" bleeder on the RH cylinder with two pipes on the LH cylinder.
(if not bodged and modified)
So Andrews problem is probably that he is trying to fit a RH cylinder on the LH side.

Re: Rear Brake Cylinders

PostPosted: Thu Aug 17, 2023 4:25 pm
by Andrew Morris
StefanM wrote:Correct cylinders for 1256 74-79 self adjusting lockheeds are as follows:
RH 91041130, 4242-626, LW11626, 19mm and 1/4-3/8" ports, flat slotted piston.
LH 91041181, 4241-378, LW11378, 19mm and 3/8-3/8" ports, flat slotted piston.

So they all just have the 1/4" bleeder on the RH cylinder with two pipes on the LH cylinder.
(if not bodged and modified)
So Andrews problem is probably that he is trying to fit a RH cylinder on the LH side.


Thats it! exactly ,thanks for the codes :D

Andrew