orangepeel61 Posted July 14, 2019 Share Posted July 14, 2019 I need to change the seals in my brake master cylinder but I'm having trouble identifying the cylinder. There is a part number on the bottom but I've only been able to read some of it: LOCKHEED .70 32 1 426 Not sure if there should be numbers in the gaps and the last 6 could be an 8. The car is a 1987 1700 Supersprint Hoping someone can throw some light on it. Link to comment Share on other sites More sharing options...
Nigel Riches Posted July 15, 2019 Share Posted July 15, 2019 G'day Orangepeel61.I have been down this road in the last few years, the seal kit number I have is SSB1210 these M/C were originally fitted to Vauxhall Victor, Ventora and Viva in the 1970's. The packet has an English name and address. Nelson Stokes Ltd. Highfield Rd. Camelford. PL32 9RA. Cornwall. P. 1840 213711. E. enquiries@nelsonstokes.com. W. www.nelsonstokes.com.If you need a new complete new old stock M/C I can point you in the direction of a company here in Christchurch NZ with some on the shelf, I bought one a few years back, it took a bit of time to get all the preserving goop off it, and I put new seals in as the originals would have been getting on a bit.Be very careful with the brake differential pressure contact, I broke two, and eventually gave up and plugged the port with a bolt, they are made from unobtainium, and very fragile, this will need removing if you change O rings on the piston for this sensor.Get back to me if you need info, PM best as I don't seem to get replies from these pages, Google thinks they're all spam.Have fun.Nigel. Link to comment Share on other sites More sharing options...
orangepeel61 Posted July 15, 2019 Author Share Posted July 15, 2019 Thanks NigelThat's given me something to go on.I don't think I've got a differential pressure contact, there's a blanked off port at the back end, maybe someone had the same problem! but thanks for the warning.I need to do some more research, my problem is the brake lights are not coming on until the pedal has firm resistance, the switch is hydraulic on the rear circuit, my initial thought was the master cylinder rear chamber wasn't working properly because changing the switch made no difference but maybe it's a differential issue.Think I need to Jack up the back end and see if the rear brakes are actually working then bleed the system and see if that has any effect.CheersNeil. Link to comment Share on other sites More sharing options...
Nigel Riches Posted July 15, 2019 Share Posted July 15, 2019 Neil, glad to have helped.These brake light switches are not very good in the hydraulic actuation system, there is a bleed nipple adjacent to the switch on "T" connector from the M/C, have you bled that at all? is the switch mounted on the forward horizontal port of the "T" connector, not the top one? The other thing to check would be the electrical resistance of the contacts in the switch, if they are corroded, the switch will not work well, and there isn't a repair for this, but as you have changed the switch, however the new switch maybe old, if you follow, The differential sensor is on the underside of the M/C with a wire attached, about where the pipes for the front brakes attach, the blanked off port on the rear is access to the differential actuator piston, the plastic sensor contact needs to be removed before you can withdraw the piston, which is a real prick of a thing to remove and refit, there are two very small "O" rings on it, these are in the kit, If you have lost one of the brake circuits the warning light on the dash should illuminate, if the bulb is Ok, this is due to the differential piston moving one way and contacting the pin in the plastic jobby under the M/C, grounding the light circuit, if the light isn't illuminating and the car is braking OK then the switch, even though new may be the problem.Nigel. Link to comment Share on other sites More sharing options...
orangepeel61 Posted July 16, 2019 Author Share Posted July 16, 2019 Nigel The switch is mounted remotely and there's no bleed nipple, there's no differential sensor under the M/C either. (Presumably there must be one somewhere!)Thinking about what you said regarding the warning light, it seems unlikely that the rear brakes aren't working. (The warning light tests ok)I need to bleed the system before I go any further, just short of someone to pump the pedal at the moment.Thanks for your thoughtsNeil. Link to comment Share on other sites More sharing options...
SM25T Posted July 16, 2019 Share Posted July 16, 2019 You need an Ezibleed system that uses air pressure from a tyre to pressurise the master cylinder. However, suggest you don't put brake fluid in the reservoir bottle as they recommend .... and dont use too high a pressure. Link to comment Share on other sites More sharing options...
orangepeel61 Posted July 16, 2019 Author Share Posted July 16, 2019 Thanks for the suggestion SM25T, couldn't wait any longer so bought an Ezibleed.I've done the whole system now but it's made no difference!Contrary to my last post there is a differential sensor where Nigel suggested, must have mislaid my glasses at that point.The rear brakes are working but not on initial application of the pedal, they start working when the brake lights come on as pressure builds up. This indicates that the switch is doing its job.So it looks like it's the differential actuator in the M/C but I can't understand why the warning light hasn't come on? So still looking for a repair kit. Link to comment Share on other sites More sharing options...
ncm Posted July 16, 2019 Share Posted July 16, 2019 The rear brakes are working but not on initial application of the pedal, they start working when the brake lights come on as pressure builds up. This indicates that the switch is doing its jobIf your car has drum rear brakes this could indicate that they require adjustment, the initial pedal movement taking up the excess slack, pressure only building once the shoes make contact with the drum.Brian. Link to comment Share on other sites More sharing options...
orangepeel61 Posted July 16, 2019 Author Share Posted July 16, 2019 Yes it does have drum rear brakes and I replaced the shoes a few weeks ago!Don't want to count my chickens but I think you may have it! Thanks! Link to comment Share on other sites More sharing options...
orangepeel61 Posted July 17, 2019 Author Share Posted July 17, 2019 Adjusted the rear brakes up but it made no difference, thanks for the idea Brian, it was worth a shot. Link to comment Share on other sites More sharing options...
ncm Posted July 17, 2019 Share Posted July 17, 2019 Is this a new problem or have you only just noticed it? I ask because when I put my 1990 De-dion car on the road a fellow motorist kindly informed me that I "had no f'in brake lights", which I replied to with a good shove on the pedal to show that, actually, I did have the requisite illumination... To investigate what was happening I wired a warning lamp from the brake switch and found that it was possible, especially in slow moving traffic, to stop the car using light application of the brakes without illuminating the brake lights. I gave up on the pressure switch at this point and engineered a mechanical switch operated from the brake pedal, set up so that the lights come on as the slack in the pushrod is being taken up. Oddly enough Caterham changed to a mechanical set up sometime in the 90's....Brian. Link to comment Share on other sites More sharing options...
orangepeel61 Posted July 17, 2019 Author Share Posted July 17, 2019 I can't say if it's a new problem or not but I've only just noticed it!A guy in a MGB pointed it out to me, to which I stood on the brake pedal and showed him the lights were fine! It was only later when I checked more carefully I noticed the problem.I'm sure, like you I could pull up in slow moving traffic without the brake lights coming on. The MGB driver can confirm this.The car was MOT'd a few weeks ago and they didn't notice anything wrong, I'm convinced nothing has changed since then.It has crossed my mind that it has always been like this, if an MOT does spot it, how do you know? Added to that is the fact that the brakes appear to work fine! I have contemplated fitting a mechanical switch but hesitant because I don't want to hide an issue if there is a real problem but I'm coming around to your way of thinking.Would be interesting to find out if anyone else has experienced this. Link to comment Share on other sites More sharing options...
ncm Posted August 4, 2019 Share Posted August 4, 2019 Looks like it's just the two of us then! Brian. Link to comment Share on other sites More sharing options...
ECR Posted August 4, 2019 Share Posted August 4, 2019 1990 DeDion, and I have been accused of not braking for corners on track...... Link to comment Share on other sites More sharing options...
patibbitts Posted August 5, 2019 Share Posted August 5, 2019 The last thing you want to do is show followers that you are braking! Don't you just hate the current driving technique of braking for every corner, every car that comes the other way, or every other reason to faulter at going forwards! I find the general quality of driving in the UK abismal, but now, realise that 99% of drivers have no empathy for proper driving technique, and 'reading' the white lines. I very often follow poor drivers (for a short while) - thinking they must have poor eyesight, when they brake for almost no reason at each bend in the road, or because another car comes the other way! I've started flashing my headlights every time they needlessly brake, to let them know what a terrible experience it is to follow them. Just can't believe the UK has such bad drivers! Link to comment Share on other sites More sharing options...
orangepeel61 Posted August 5, 2019 Author Share Posted August 5, 2019 Have now fitted an additional mechanical switch, the brake lights (and the brakes) are now working fine.I'm convinced that this is a design fault, surely a hydraulic switch should be fitted in the primary circuit not the secondary.I don't think it is just the two of us Brian, there must be others out there! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 20, 2020 Member Share Posted March 20, 2020 Did you ever get the correct part number for the cylinder?PowerTrack Ltd look as if they could help.Jonathan Link to comment Share on other sites More sharing options...
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