JohnTB Posted June 23, 2015 Report Share Posted June 23, 2015 Just changed my Master Cylinder. In bleeding the system after fitting, back brakes bled up fine, but I have a problem getting air out of the front. Resvoir full, back off near side nipple, pedal slowly to floor, air bubbles expelled. Lock off nipple and let pedal come up and try again (just a usual brake bleed) Do this again and again but no matter how many times bubbles still appear and I can't get any pedal resistance. Make sure no leaks anywhere (there aren't) and try again. Same result, pedal travels to floor. Won't stiffen up with pumping. I notice that not very much fluid is disappearing considering the amount of times I've tried. I also notice that when the pedal is comming up from the floor, bubbles are comming up into the resvoir from the small hole at the bottom of the rear of the resovoir (In the larger of the two parts, the one servicing the front brakes). I suspect that the tip valve in the new Master Cylinder is the cause of this by sticking open and thus not allowing much pressure to the calipers and also allowing in air (but from where?). From what I understand of the master cylinder, the tip valve should close once the pedal is depressed and thus pressurise the system. Will very much appreciate any observations, experiences etc Quote Link to post Share on other sites
Guest ntc Posted June 23, 2015 Report Share Posted June 23, 2015 How old is the master cylinder? Quote Link to post Share on other sites
JohnTB Posted June 23, 2015 Author Report Share Posted June 23, 2015 Hello Neil, New from Moss last week ! Quote Link to post Share on other sites
Guest ntc Posted June 23, 2015 Report Share Posted June 23, 2015 Check it is not old stock John ,ask them for the truth and accept no less as there has been problems a search will tell you all Quote Link to post Share on other sites
Jersey Royal Posted June 23, 2015 Report Share Posted June 23, 2015 (edited) Check it is not old stock John ,ask them for the truth and accept no less as there has been problems a search will tell you all Neil The thread I started, some twenty odd pages on TRW master cylinders was "lost in an update" apparently Below is a link to the original thread no longer there. http://www.tr-register.co.uk/forums/index.php?showtopic=35138&view=getnewpost I would hope they would have junked any of the old ones. Cheers Guy Edited June 23, 2015 by Jersey Royal Quote Link to post Share on other sites
Steves_TR6 Posted June 23, 2015 Report Share Posted June 23, 2015 I had these symptoms on y last car. Turned out to be a damaged flare on the pipe entering the master cylinder, was sucking in air but not leaking. Steve Quote Link to post Share on other sites
JohnTB Posted June 24, 2015 Author Report Share Posted June 24, 2015 Thanks Folks, Have tried the thread link but nothing specific comes up. It seems I need the heading of the thread to get the info up by putting it into 'search'. Appreciate advice Ta! John B Quote Link to post Share on other sites
Peter Cobbold Posted June 24, 2015 Report Share Posted June 24, 2015 Thanks Folks, Have tried the thread link but nothing specific comes up. It seems I need the heading of the thread to get the info up by putting it into 'search'. Appreciate advice Ta! John B Guy's original past was pulled by the forum police. It was in 2012. The gist of the thread is in another post from 2012: http://www.tr-register.co.uk/forums/index.php?/topic/36381-spongy-brakes-even-after-full-bleed/ If Guy can recall the excat title of his thread it might have been cached by Google. Peter Quote Link to post Share on other sites
Jersey Royal Posted June 24, 2015 Report Share Posted June 24, 2015 Guy's original past was pulled by the forum police. It was in 2012. The gist of the thread is in another post from 2012: http://www.tr-register.co.uk/forums/index.php?/topic/36381-spongy-brakes-even-after-full-bleed/ If Guy can recall the excat title of his thread it might have been cached by Google. Peter Peter Thread was titled Brake Master leaks, Great!! From my research it was zapped, official line they dont know what happend to it and wasnt removed deliberately. Still dont believe that. I do have the majority of the posts as I had it set up to email notifications etc, but it would take ages to copy and paste the whole lot. Cheers Guy Quote Link to post Share on other sites
Peter Cobbold Posted June 24, 2015 Report Share Posted June 24, 2015 Still dont believe that. Neither do I. Cant find it. But if the old stock of cr*p m/cyls has been liberated from the warehouses, doubtless the topic will return. And this time we'll log the posts. Peter Quote Link to post Share on other sites
TR NIALL Posted June 24, 2015 Report Share Posted June 24, 2015 Well I have a Leaky one that was on a Car for 1 Week only and I also have a Brand New one from the same source that I'm afraid to fit and waste more of my Time and Effort on,both bought at Stoneleigh about 6yr ago and made by TRW. Quote Link to post Share on other sites
Peter Cobbold Posted June 25, 2015 Report Share Posted June 25, 2015 @ JohnTB I think that pulled thread included recommendations to forget new m/cyls and have the old m/cyl resleeved in stainless: I have this bookmarked: http://www.pastparts.co.uk/reman.htm Peter Quote Link to post Share on other sites
JohnTB Posted June 26, 2015 Author Report Share Posted June 26, 2015 Thanks folks for all your help/pointers etc. I now have it solved (so far, so good!) Took the reservoir off the new M/Cyl and used screwdriver to push piston. Tip valve did nothing. Tried again, but his time pushed tip valve gentley and it dropped. Couldn't get Tip Valve to stick again, examined and it does look OK. Re-fitted reservoir and mounted M/Cyl in vice. Put some fluid in reservoir and pushed piston with screwdriver. Fluid squirted out of both holes. Put stoppers in both holes and fitted M/Cyl (with some fluid still in reservoir). Attached both hydrolics and bled system. Took best part of yesterday, (and a litre and a half of fluid - but then again I'm using Toyota Hi-Lux 4 pots). Still got bubbles back into the large bit of the reservoir initially, but I guess if the tip valve is working OK then you would until the top bit of the system was purged and the air was being forced to go in the direction of the calipers. Believe I've got all air out. I made sure there were three complete clear of bubbles cycles at each wheel. Pedal now hard and no feel of any sponginess. I'm feeling pretty confident that my previous problems are now solved. However, in view of the comments, I will pay particular attention over the coming weeks! All the best John B Quote Link to post Share on other sites
Steves_TR6 Posted June 26, 2015 Report Share Posted June 26, 2015 Good work John. I too have the Toyota 4 pot calipers, what pads are you using? Steve Quote Link to post Share on other sites
JohnTB Posted June 27, 2015 Author Report Share Posted June 27, 2015 Hello Steve, I'm using Mintex. Thought I'd kept the lable from the box - obviously very carefully filed somewhere ! John B Quote Link to post Share on other sites
astontr6 Posted June 27, 2015 Report Share Posted June 27, 2015 JohnTB, What year Toyota Hi-Lux callipers are you using? or even better do you have a part number? Thanks, Bruce. Quote Link to post Share on other sites
Steves_TR6 Posted June 27, 2015 Report Share Posted June 27, 2015 I'm on minted too John. I posted a thread about this brake conversion previously, have a search as I included part numbers and prices. Steve Quote Link to post Share on other sites
astontr6 Posted June 27, 2015 Report Share Posted June 27, 2015 Steve, I have tried all sorts of combinations in the search box, no luck, can you remember what the heading was? Thanks, Bruce. Quote Link to post Share on other sites
Steves_TR6 Posted June 28, 2015 Report Share Posted June 28, 2015 Hi Bruce, if you search for Toyota brake then lots come up, the thread in question is called 'how to improve the brakes' my contributions start on page 2, it's a long thread. Enjoy the read :-) Steve Quote Link to post Share on other sites
astontr6 Posted June 28, 2015 Report Share Posted June 28, 2015 Steve, I have found it now! Thanks! But I have another question did you ever fit the larger size Land Rover Master Cyl. and were the internal design and make up of that M/Cyl the same as the TR one except the bore size and fluid tank? If it is, my intention would be to bore out the TR M/Cyl and use the LR internals! Bruce. Quote Link to post Share on other sites
Steves_TR6 Posted June 28, 2015 Report Share Posted June 28, 2015 Hi Bruce I did a test fit of the 1" master cylinder and found the pedal too hard. I think the 'leverage' of the considerably larger piston size was too great. The intermediate size might be perfect, ala goldilocks..., but I haven't gone any further with the experiment. Brakes are good, pedal travel is a little long but that's mostly due to the silicone brake fluid, there's another thread that does the calls on this and the net effect is half to an inch of additional pedal travel with silicone Let us know how you get on, brakeparts dot co dot UK were very cheap,helpful, reliable so recommended. Steve Quote Link to post Share on other sites
astontr6 Posted June 28, 2015 Report Share Posted June 28, 2015 Steve, Regarding pedal travel : Is your servo unit original if not when you fitted a new master cyl. or fitted new seals or servo unit, Did you check the push rod clearance on the servo unit with a straight edge across the casing and push rod. It s/b 0.011 to 0.016"! I worked on another member's TR6 where a new complete unit had been fitted by a TR Specialist and found that this clearance was way out and to my surprise, it affected the pedal travel, as can a worn servo. At the time I originally thought that it was only air in the system!!! Bruce. 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.