Jersey Royal Posted June 23, 2008 Report Share Posted June 23, 2008 Hi All, I had a problem in frogland with the brakes which seemed to be an intermitant, sometimes the pedal would become softer and require a second pump. I have readjusted my rear brakes and handbrake, and bleed the rears. Not bleed front yet though. I have been reading the Buckeye Technical Articles and have a query on the Master Cylinder Seals. The more common tipping valve and/or the secondary piston supply valve problem is that they leak. When they leak, the piston merely pushes the fluid back into the reservoir when the pedal is pressed. The one I've had the most difficulty with is secondary supply valve. As the seals deteriorate, some of the seal material builds up around the valve area at the back of the cylinder. This area must be cleaned thoroughly during the rebuild. A leaking tipping valve and/or the secondary piston supply valve can be detected by observing the reservoir level when the pedal is pressed. A slight disturbance in the fluid is usually observable when a little fluid is pushed back in the reservoir as the valve is being closed. If the level is the reservoir increases when the pedal is pressed, then the seal is not sealing. Does this mean that if the seals are functioning correctly there should be absolutely no movement in fluid Thanks for your advise. Cheers Guy Quote Link to post Share on other sites
88V8 Posted June 23, 2008 Report Share Posted June 23, 2008 Does this mean that if the seals are functioning correctly there should be absolutely no movement in fluid Hope it wasn't too brown-pant. There has to be some movement, because you are pushing fluid towards the slave cylinders, but if anything the level in the reservoir should drop a little when you press the pedal. What he is saying is that if it rises when the pedal is pressed, there is a problem, because the fluid is being pushed out of the cylinder but is taking the line of least resistance and leaking back into the reservoir through the tipping valve. Was the pedal actually soft? Or was there just more travel than usual? Might it have been the infamous 'caliper piston knock-back' due to some play in a front wheel bearing? Ivor Quote Link to post Share on other sites
Jersey Royal Posted June 23, 2008 Author Report Share Posted June 23, 2008 Hi Ivor, It wasnt too brown pant like, it actually seems to happen at slow speeds. Am going to take car for a spin tomorrow morning to refresh the memory of symptoms, but did seem to be a soft pedal with alot more movement than normal. I have looked at master cylinder at the front section seems to rise a fraction (1mm) when pedal pressed, rear section seems to have no movement. New wheel bearings were fitted last year and yeah will check for play. Thanks muchly Guy Quote Link to post Share on other sites
pinky Posted June 23, 2008 Report Share Posted June 23, 2008 Hi Ivor, It wasnt too brown pant like, it actually seems to happen at slow speeds. Am going to take car for a spin tomorrow morning to refresh the memory of symptoms, but did seem to be a soft pedal with alot more movement than normal. I have looked at master cylinder at the front section seems to rise a fraction (1mm) when pedal pressed, rear section seems to have no movement. New wheel bearings were fitted last year and yeah will check for play. Thanks muchly Guy hi guy, hope you had a good holiday, except for the brakes, I would have thought it was a leak some were, not a big leak possible intermittent leak, you could always follow the pipe back, from the master cylinder checking all the pipe fittings etc, keep pressure on the clutch peddle with a section of wood jamming the pedal down might show it self will send the other information over you asked for in the next couple of days did you read the item on the front bumper height we discussed regards pinky Quote Link to post Share on other sites
Jersey Royal Posted June 23, 2008 Author Report Share Posted June 23, 2008 (edited) hi guy, hope you had a good holiday, except for the brakes, I would have thought it was a leak some were, not a big leak possible intermittent leak, you could always follow the pipe back, from the master cylinder checking all the pipe fittings etc, keep pressure on the clutch peddle with a section of wood jamming the pedal down might show it self will send the other information over you asked for in the next couple of days did you read the item on the front bumper height we discussed regards pinky Hi Pinky, I did indeed, good to meet up with my East Saxon friends, i covered 1350 miles in all. I read the thread on the bumper height and was suprised, funnily enough one of the Trs on the French trip had the same bumpers. Will check pipes for leaks although havent had any fluid loss from reservoir but certainly worth a check over. You never know could be my imagination. Cheers Pinky Guy Edited June 23, 2008 by Jersey Royal Quote Link to post Share on other sites
badshead Posted June 23, 2008 Report Share Posted June 23, 2008 I have looked at master cylinder at the front section seems to rise a fraction (1mm) when pedal pressed, rear section seems to have no movement. On my 73 CR, the front section (assuming you mean nearest front of car) is the rear brake reservoir. Quote Link to post Share on other sites
Jersey Royal Posted June 23, 2008 Author Report Share Posted June 23, 2008 (edited) On my 73 CR, the front section (assuming you mean nearest front of car) is the rear brake reservoir. Badshead, Thats what i meant front portion of reservoir which is the rear brake . Have also checked the push in type non return valve on the servo and that is working correctly. Cheers Guy Edited June 23, 2008 by Jersey Royal Quote Link to post Share on other sites
Jersey Royal Posted June 30, 2008 Author Report Share Posted June 30, 2008 (edited) Hi All, Update, I have adjusted handrake and rear brakes, bleed both front and rears. Brakes do now pull up . However there is still a soft pedal when i first use them in the morning or if the car is cold, doesnot really install alot of confidence. I have checked the return valve on the servo,and thats fine. The level still rises in the reservoir, when i apply the brake, and have noticed small black particles in it, which seems to me to indicate the seals are past their best. I had already ordered a master brake seal kid from Revington and await its delivery along with a few other bits and bobs. Question is. Am i doing the right thing ? i see that Tr Shop do a complete Master for 85 squid and with servo 185. There Master appears to have Lucas written on the side of it whereas my existing doesnt. Has anyone fitted Servo and or master from Tr Shop, and could confirm its quality or otherwise? I have less than two weekls to sort this prior to Le Mans. Your thoughts are appreciated as always Cheers Guy Edited June 30, 2008 by Jersey Royal Quote Link to post Share on other sites
RobinTR6 Posted June 30, 2008 Report Share Posted June 30, 2008 Hi All, Update, I have adjusted handrake and rear brakes, bleed both front and rears. Brakes do now pull up . However there is still a soft pedal when i first use them in the morning or if the car is cold, doesnot really install alot of confidence. I have checked the return valve on the servo,and thats fine. The level still rises in the reservoir, when i apply the brake, and have noticed small black particles in it, which seems to me to indicate the seals are past their best. I had already ordered a master brake seal kid from Revington and await its delivery along with a few other bits and bobs. Question is. Am i doing the right thing ? i see that Tr Shop do a complete Master for 85 squid and with servo 185. There Master appears to have Lucas written on the side of it whereas my existing doesnt. Has anyone fitted Servo and or master from Tr Shop, and could confirm its quality or otherwise? I have less than two weekls to sort this prior to Le Mans. Your thoughts are appreciated as always Cheers Guy Yes bought one last weekwith new servo (special offer) both on and transformed the brakes. Although bled twice they are still soft when first used the harden up after first push and stay hard , not sure if I should be worried but they are a lot better than before. Quote Link to post Share on other sites
stuart Posted July 1, 2008 Report Share Posted July 1, 2008 (edited) Guy if you have black bits in your fluid (ooer missus ) then it does sound as if either seals are giving up or a flexi is starting to break down internally. TR Shop complete kit is a very good deal although I havent tried one yet. A soft or spongy pedal can sometimes be cured by pumping the pedal a couple of times and then jam the pedal down with a block of wood from the seat or if you have it one of those fancy pedal locks that MOT testers use and leave overnight. Makes quite a difference especially if you have been bleeding the system which does tend to make the fluid froth a bit. Stuart. Edited July 1, 2008 by stuart Quote Link to post Share on other sites
Jersey Royal Posted July 5, 2008 Author Report Share Posted July 5, 2008 Guy if you have black bits in your fluid (ooer missus ) then it does sound as if either seals are giving up or a flexi is starting to break down internally. TR Shop complete kit is a very good deal although I havent tried one yet. A soft or spongy pedal can sometimes be cured by pumping the pedal a couple of times and then jam the pedal down with a block of wood from the seat or if you have it one of those fancy pedal locks that MOT testers use and leave overnight. Makes quite a difference especially if you have been bleeding the system which does tend to make the fluid froth a bit.Stuart. Hi Stuart, Have checked all rubber pipework, which i had replaced last year with braided type on all but the rear left, that has now been replaced. I have removed the master cylinder stripped it and its all cleaned up. The cylinder itself looks fine but the rear seal on the piston could be slightly worn. Finally my seal kit has arrived today. My query is , i know i should lubricate the bore with some brake fluid, but what about the new seals, i have a sachet of red rubber grease how much should i put on the rubber seals? should i go on the pistons also. A bit like how long is a piece of string!, a little smear a coating. Thanks again Cheers guy Quote Link to post Share on other sites
stuart Posted July 5, 2008 Report Share Posted July 5, 2008 Hi Stuart, Have checked all rubber pipework, which i had replaced last year with braided type on all but the rear left, that has now been replaced. I have removed the master cylinder stripped it and its all cleaned up. The cylinder itself looks fine but the rear seal on the piston could be slightly worn. Finally my seal kit has arrived today. My query is , i know i should lubricate the bore with some brake fluid, but what about the new seals, i have a sachet of red rubber grease how much should i put on the rubber seals? should i go on the pistons also. A bit like how long is a piece of string!, a little smear a coating. Thanks again Cheers guy Guy when fitting seals I dip them in brake fluid first. pistons also cover with clean fluid and only use the red grease under the dust seals and a smear in the push rod cup. Stuart. Quote Link to post Share on other sites
Jersey Royal Posted July 6, 2008 Author Report Share Posted July 6, 2008 Hi, Master all back together and system has been bleed, wheels back on. Took it for a short test, brakes pull up as before and seem ok. Not decided if its any better really, certainly not worse. I had parked car outside garage top down whilst i wrote this post, looked out the window and the clouds have just opened a massive heavy shower, car now soaked, and the bonnet was up I got soaked bringing her in. What is the max and min level of fluid in the master, as i have filed up to internal division line, as i seem to get a seepage out of the top, maybe it wasnt tight enough? Regards Guy Quote Link to post Share on other sites
PILKIE Posted July 6, 2008 Report Share Posted July 6, 2008 Hi Guy. I noticed that if the reservoir had a little to much fluid in it,the high G forces of acceleration will cause it to seep out of the caps back edge. By experimenting,I took the level down to a point where this did not happen,and its still got plenty of fluid in! Dave Quote Link to post Share on other sites
88V8 Posted July 6, 2008 Report Share Posted July 6, 2008 I had parked car outside garage top down whilst i wrote this post, looked out the window and the clouds have just opened a massive heavy shower, car now soaked, and the bonnet was up I got soaked bringing her in. What is the max and min level of fluid in the master, as i have filed up to internal division line, as i seem to get a seepage out of the top, maybe it wasnt tight enough? Rain? In Jersey What's the world coming to... I fill mine well above the partition. A smear of red grease on the cap washer may help get a better seal, will also make it easier to undo. Ivor Quote Link to post Share on other sites
Jersey Royal Posted July 6, 2008 Author Report Share Posted July 6, 2008 Thanks for you input Dave and Ivor, Will give it a go Cheers Guy Dirty black clouds have now gone They are heading in your direction Suns out here now, just about to light the bbq Quote Link to post Share on other sites
PILKIE Posted July 6, 2008 Report Share Posted July 6, 2008 Dirty black clouds have now gone They are heading in your direction Suns out here now, just about to light the bbq Just had a few dump their mother load on my neck of the mainland! I was having a nice restful doze until a sopping wet casper cat jumped on me wanting a dry off and cuddle coz he got wet!! Quote Link to post Share on other sites
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