ijonsson Posted July 26, 2022 Report Share Posted July 26, 2022 (edited) TR2 has such a simple system and still I can't figure out why pressure builds up until brakes stay on. For the moment I have an emergency solution, as I had an aftermarket brake servo installed, (and did blame it for the pressure build up and removed it) there is a bleed nipple in its place. When I feel the pedal getting lost of play, I just have to bleed the system just a few drops, and I can drive on. I have just 5 year old brake hoses, and just a week ago I replaced all the seals in the master cylinder. I also checked the non return valve in the master cylinder, and it seems to work. What would happen if I took away the valve (as in the picture)? The master cylinder was sleeved by Past Parts, could something have been "blocked" when doing that? There has been no problem bleeding the system, I use Easy-bleed to pressurize the system. Edited July 26, 2022 by ijonsson Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 26, 2022 Report Share Posted July 26, 2022 Is the pedal push rod a loose fit in the master cyl when no pedal pressure is applied? Is there not enough free play? Slack the adjusting stop bolt and nut to let the pedal release the push rod Quote Link to post Share on other sites
ijonsson Posted July 26, 2022 Author Report Share Posted July 26, 2022 No, it isn't. Thank you, I realize that the piston seal might be blocking the hole in the sleeve if the piston isn't returning fully. I'll try that first thing tomorrow! Quote Link to post Share on other sites
ewan2 Posted July 27, 2022 Report Share Posted July 27, 2022 Has the car got Drum brakes. I had problems with replacement shoes bedding in. The linings were too thick and caused the brakes to grab. Ewan Quote Link to post Share on other sites
Dic Doretti Posted July 27, 2022 Report Share Posted July 27, 2022 I also had this problem. The car would stop and only way to get it moving was to release the pressure in the hydraulic system. It was cured by slackening off the adjuster as Peter W has suggested. Cheers Richard Quote Link to post Share on other sites
stuart Posted July 27, 2022 Report Share Posted July 27, 2022 12 hours ago, BlueTR3A-5EKT said: Is the pedal push rod a loose fit in the master cyl when no pedal pressure is applied? Is there not enough free play? Slack the adjusting stop bolt and nut to let the pedal release the push rod That`ll be what it is, it only needs to be a gnats too little clearance and as it warms up it holds pressure in the system. Stuart. Quote Link to post Share on other sites
mikej Posted July 27, 2022 Report Share Posted July 27, 2022 Possibility the sleeve has moved, take top off and poke a very thin wire down the forward most fluid hole, it should go through to the piston and also confirm the seal is not blocking the hole. Just a thought. MikeJ Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 27, 2022 Report Share Posted July 27, 2022 7 hours ago, mikej said: Possibility the sleeve has moved, take top off and poke a very thin wire down the forward most fluid hole, it should go through to the piston and also confirm the seal is not blocking the hole. Just a thought. MikeJ Good check. Quote Link to post Share on other sites
John McCormack Posted July 28, 2022 Report Share Posted July 28, 2022 Not in this instance as it has been done very recently, but if the brake fluid isn't changed regularly the very small hole can block with debris in the fluid. Quote Link to post Share on other sites
ijonsson Posted July 28, 2022 Author Report Share Posted July 28, 2022 On 7/27/2022 at 10:18 AM, ewan2 said: Has the car got Drum brakes. I had problems with replacement shoes bedding in. The linings were too thick and caused the brakes to grab. Ewan Yes it's a TR2 and got drums all around, and not new shoes. I've been driving the car for 5 years. Quote Link to post Share on other sites
ijonsson Posted July 28, 2022 Author Report Share Posted July 28, 2022 (edited) On 7/27/2022 at 11:22 AM, Dic Doretti said: I also had this problem. The car would stop and only way to get it moving was to release the pressure in the hydraulic system. It was cured by slackening off the adjuster as Peter W has suggested. Cheers Richard Yes, I was just about to write a post about that the problem is solved, thanks to Peters advice. When I put in the servo, I also tried to level the pedals with the help of those adjuster screws, so the problem occurred after fitting the servo and that's why I at first blamed the servo. Edited July 28, 2022 by ijonsson Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 31, 2022 Report Share Posted July 31, 2022 (edited) To change the pedal heights you would need adjustable push rods in the master cylinder, to reduce the push rod length. You would set the pedal height with the adjusting screws in the master cylinder support bracket then set the push rod length to give free play as required. Think about the pedal movement in the car. If the pedal touches the bulkhead on RH drive cars it will wear the wiring loom. Not sure if there is wiring behind the pedals on LH drive Peter W Edited July 31, 2022 by BlueTR3A-5EKT Quote Link to post Share on other sites
ijonsson Posted August 1, 2022 Author Report Share Posted August 1, 2022 I have never seen adjustable pushrods, do they have a longnut in the end or in the shaft? No problem with wire-loom in LH drive cars, fusebox is in the same place as in RH drive cars. And, in my car I have moved the light dip switch to a stalk on the steering column, so none of those wires are on the floor. /Inge Quote Link to post Share on other sites
stuart Posted August 1, 2022 Report Share Posted August 1, 2022 1 hour ago, ijonsson said: I have never seen adjustable pushrods, do they have a longnut in the end or in the shaft? No problem with wire-loom in LH drive cars, fusebox is in the same place as in RH drive cars. And, in my car I have moved the light dip switch to a stalk on the steering column, so none of those wires are on the floor. /Inge There is these https://www.merlinmotorsport.co.uk/p/adjustable-push-rod-clevis-gmc-clv https://www.merlinmotorsport.co.uk/p/girling-extended-push-rod-5-16-unf-gmc-pr Stuart. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted August 1, 2022 Report Share Posted August 1, 2022 1 hour ago, ijonsson said: I have never seen adjustable pushrods, do they have a longnut in the end or in the shaft? No problem with wire-loom in LH drive cars, fusebox is in the same place as in RH drive cars. And, in my car I have moved the light dip switch to a stalk on the steering column, so none of those wires are on the floor. /Inge MGA had the set up I have described. Buy the items Stuart has suggested as they are a fraction of the MG price. But you would have to cut the mushroom off the push rod to fit and adjust its length. Peter W Quote Link to post Share on other sites
ijonsson Posted August 2, 2022 Author Report Share Posted August 2, 2022 (edited) 22 hours ago, stuart said: There is these https://www.merlinmotorsport.co.uk/p/adjustable-push-rod-clevis-gmc-clv https://www.merlinmotorsport.co.uk/p/girling-extended-push-rod-5-16-unf-gmc-pr Stuart. OK, thanks! Now I got it, in my mind it was the rod itself that was adjustable, should have known better. A couple of these I can fix myself, I already made some for the handbrake system, both for the TR2 and other cars. A winter job. FIrst I'll attend the annual Swedish TR club meeting this weekend and within a month the European TR meeting i Båstad, south of Sweden. /Inge Edited August 2, 2022 by ijonsson Quote Link to post Share on other sites
ijonsson Posted August 19, 2022 Author Report Share Posted August 19, 2022 Brake problem solved thanks to suggestions here. But, I still had one front wheel not locking up but braking and getting warm. After taking off the drum, I noticed that one or maybe both wheel cylinders weren't fully going back. Thinking the springs weren't strong enough, by chance I found a pair of original springs and noticed that they are stronger than the repro springs. I fitted the old springs, and now everything works OK. Can the reason the wheel cylinders aren't going back so easily on one side, be the consequence of brakes overheating due to the original problem with pressure staying on? Might the seals be damaged? Quote Link to post Share on other sites
stuart Posted August 19, 2022 Report Share Posted August 19, 2022 1 hour ago, ijonsson said: Brake problem solved thanks to suggestions here. But, I still had one front wheel not locking up but braking and getting warm. After taking off the drum, I noticed that one or maybe both wheel cylinders weren't fully going back. Thinking the springs weren't strong enough, by chance I found a pair of original springs and noticed that they are stronger than the repro springs. I fitted the old springs, and now everything works OK. Can the reason the wheel cylinders aren't going back so easily on one side, be the consequence of brakes overheating due to the original problem with pressure staying on? Might the seals be damaged? Possible if the fluid got really hot. Stuart. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted August 19, 2022 Report Share Posted August 19, 2022 13 minutes ago, stuart said: Possible if the fluid got really hot. Stuart. I think the drums would have to have been glowing for that to really affect the fluid and the seals. Pump 100ml of new brake fluid through both the furthest front cylnders if you are really concerned. In use the brakes will get very hot, if they have been overheated you will notice burning or glazing in the drums and on the shoe friction material. Off at a tanget - I have a few spare new and used Lockheed front and rear brake parts including back plate & springs somewhere - is any one interested? Peter W Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.