timbo Posted April 24, 2013 Posted April 24, 2013 So I have known for a while that cvrt m/c's are superficially the same as land rover series 3 ones, but the cvrt uses mineral oil, not brake fluid. My theory is this, have bought a series 3 m/c (£15), and the piston and components look identical to cvrt. I also have a stock of seal rebuild kits for cvrt (also £15). Fit the cvrt seals to the lr mc, and hey presto you have a new mc for £30 (compared to the £80-£120 which seems to be the going rate for cvrt ones). Any thoughts? Am I missing something here? Cheers Tim Quote
Grasshopper Posted April 25, 2013 Posted April 25, 2013 As long as the cylinder diameter, volume and port orices are identical and the thread sizes match (or alternative banjo bolts used) then sounds perfectly feasible. Vince Quote
timbo Posted April 25, 2013 Author Posted April 25, 2013 (edited) Hi Vince It looks identical in every respect. I'm probably going to have a go at changing the seal in the next few days so ill let you know how I get on. Cheers Tim Edited April 25, 2013 by timbo Edited so i dont sound like vinces mum! Quote
sirhc Posted April 25, 2013 Posted April 25, 2013 Tim, Make sure you soak the new seals in brake oil before attempting to stretch them over the piston. Don't ask how I know this!! Chris Quote
timbo Posted April 25, 2013 Author Posted April 25, 2013 Tim, Make sure you soak the new seals in brake oil before attempting to stretch them over the piston. Don't ask how I know this!! Chris Hi Chris Yes saw that post - learning from others experience is always the best way! Cheers Tim Quote
timbo Posted April 25, 2013 Author Posted April 25, 2013 Here is a comparison of the two mc's - a new series 3 one and a very worn out CVRT one. The only discernible difference I have been able to find, apart from the seal material, is in the length of the actuating rod, which is easily sorted. Quote
sirhc Posted April 25, 2013 Posted April 25, 2013 Tim, I can't see why it won't work, let us know how you get on.. and the part number of the LR master cylinder! Chris Quote
timbo Posted April 25, 2013 Author Posted April 25, 2013 Chris Before I forget it is 90569128... I dont have any mineral oil to soak the seals at the moment, so it will take a while. Annoyingly I have an unopened 25 litre tub of ISO10 but it's on the back of my Saladin, 120 miles away..! Cheers Tim Quote
BRDM Driver Posted April 25, 2013 Posted April 25, 2013 That's a brilliant tip! I have a slow fluid leak in my Scorpion somewhere so I'll be getting the floor up soon to check the cylinders. Quote
sirhc Posted April 26, 2013 Posted April 26, 2013 Tim, There are definitely no other rubber parts in the Land Rover master cylinder which could be a problem? Pressure relief valves etc? Chris Quote
Toolman Posted April 26, 2013 Posted April 26, 2013 Chris Before I forget it is 90569128... I dont have any mineral oil to soak the seals at the moment, so it will take a while. Annoyingly I have an unopened 25 litre tub of ISO10 but it's on the back of my Saladin, 120 miles away..! Cheers Tim I've got an opened 25 lit tin though :-) only 250ml used! (fluid flywheel) MT Quote
timbo Posted April 28, 2013 Author Posted April 28, 2013 Tim, There are definitely no other rubber parts in the Land Rover master cylinder which could be a problem? Pressure relief valves etc? Chris Chris Have taken both cylinders down to bare casting. The only seals appear to be the main seal on the piston, and the smaller (non return?) seal on the end of the piston rod, both of which are included in the rebuild kit. Im going to give one of these a go in my steering brakes. Was going to put it on the main brakes but I rarely seem to use them so thought I maya as well give it a proper test..! Cheers Tim Quote
mill comms Posted May 1, 2013 Posted May 1, 2013 I need to rebuild several of these master cylinders this summer for my Sabre project. Can you please tell me why you need to replace the seals in the Land rover master cylinder for the CVRT ones. Is it a different type of rubber used?. Quote
BRDM Driver Posted May 1, 2013 Posted May 1, 2013 CVRT's use hydraulic fluid in the brakes, not brake fluid so you need to watch which type of seals you use. Quote
sirhc Posted May 1, 2013 Posted May 1, 2013 You can order seal kits from Banisters, the seals will probably be a green colour. Quote
timbo Posted May 1, 2013 Author Posted May 1, 2013 I need to rebuild several of these master cylinders this summer for my Sabre project.Can you please tell me why you need to replace the seals in the Land rover master cylinder for the CVRT ones. Is it a different type of rubber used?. The mineral oil seals seem to be a bit less 'rubbery' if there is such a word. All the ones i have seen so far seem to be a light green colour to differentiate them i presume. They are also a pig to fit hence need to be soaked. I then found I could carefully stretch it using some small pliers and ease them over the piston. The smaller seal is not a problem. If you use the land rover seals with mineral oil they will turn to mush. Similarly if you try to use brake fluid in the cvrt brakes you will end up in a big mess...! I have now completed the rebuild of the mc so Im going to try and fit and bleed them over the weekend. Will let you know how i get on. Hope this helps. I have also had a bit of welding work done on the steering box which was starting to suffer with the dreaded corner cracking. Again i will post some pics over the weekend... Cheers Timbo Quote
mill comms Posted May 2, 2013 Posted May 2, 2013 Thanks for the advice everyone. Is it Banisters from East Sussex who have the seal kits. Next question is the correct grade of oil to use, is it something like Shell Tellus Oil (hydraulic fluid)? Quote
timbo Posted May 2, 2013 Author Posted May 2, 2013 Thanks for the advice everyone.Is it Banisters from East Sussex who have the seal kits. Next question is the correct grade of oil to use, is it something like Shell Tellus Oil (hydraulic fluid)? Hello mate i use Morris lubricants ISO10 which seems to work quite well... Cheers Tim Quote
Grasshopper Posted May 2, 2013 Posted May 2, 2013 I've used Tellus (due to having a "handy supply" to hand...) with no issues. Quote
Sidewinder Posted September 10, 2013 Posted September 10, 2013 Tim, How did you get on with the LR master cylinders in the end, no problems I take it? Stripped the three m/c's out of my Spartan ready for rebuilding yesterday so just wondered if there were any updates before ordering the parts. Cheers, James Quote
timbo Posted September 10, 2013 Author Posted September 10, 2013 Tim, How did you get on with the LR master cylinders in the end, no problems I take it? Stripped the three m/c's out of my Spartan ready for rebuilding yesterday so just wondered if there were any updates before ordering the parts. Cheers, James Still working perfect mate. In fact if anything the LR one is a bit firmer....recommended...I've ordered a stack of them and the seal kits to go with them, much better than the £100+ which seems to be the going rate for cvrt ones... Cheers Tim Quote
Sidewinder Posted September 10, 2013 Posted September 10, 2013 Perfect! Just ordered the m/c's, that's this weekend taken care of! I must admit though, I was a bit surprised that the main brake m/c is the same as the steering ones, I was expecting the main brake cylinder to be a bit bigger given it's operating two calipers each with larger pistons, but I guess the steering ones must just be over spec'd? Or is it more for practical/commonality reasons should they need replacing in the field? James Quote
timbo Posted September 11, 2013 Author Posted September 11, 2013 (edited) Perfect! Just ordered the m/c's, that's this weekend taken care of! I must admit though, I was a bit surprised that the main brake m/c is the same as the steering ones, I was expecting the main brake cylinder to be a bit bigger given it's operating two calipers each with larger pistons, but I guess the steering ones must just be over spec'd? Or is it more for practical/commonality reasons should they need replacing in the field? James James I guess part commonality is a consideration but in practice it's pretty rare to make use of the main brakes anyway - they tend to stop pretty quickly once you take your foot off the gas..! Cheers Timbo Edited February 5, 2014 by timbo Quote
timbo Posted February 5, 2014 Author Posted February 5, 2014 A quick update on this...not much use of the old girl over the winter due to a few (ahem) ignition problems and a lack of time, but I have been poking around with the brakes while I have had the decks off. The LR cylinder remains very firm and responsive with no problems at all. Cheers all... Quote
ferrettkitt Posted February 5, 2014 Posted February 5, 2014 A quick update on this...not much use of the old girl over the winter due to a few (ahem) ignition problems and a lack of time, but I have been poking around with the brakes while I have had the decks off. The LR cylinder remains very firm and responsive with no problems at all. Cheers all... Extremely happy with that seen as I have bought most of the kit to redo the cylinders on my spare and ordered the oil. The assembly looks grubby but its all free and moving but leaking in places it shouldn't. [ATTACH=CONFIG]87114[/ATTACH] [ATTACH=CONFIG]87115[/ATTACH] Quote
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