Maverik Posted June 12, 2012 Share Posted June 12, 2012 Hi people, just doing some work on the Black Disco 1 (95), the master brake cylinder was on its way out so I picked up a new Lucas part NTC4991, now I'm guessing this is an early model master cyclinder as it has 4 ports on the barrel (2 front and 2 rear)... the master cyclinder I removed only has 2 ports, 1 for front and 1 for rear, its then split from what looks like a balance valve on the passanger side front inner wing. Anywhoo the question is, can anyone see a problem with me blanking the 2 extra ports off with bleed nipples or blanking plugs (i fi can find some)... i can;t see a problem, but thought i'd juts put it out there. Cheers Mav Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted June 12, 2012 Share Posted June 12, 2012 I have done this with a challenge truck not used on the road and it worked OK but not sure I would want to risk it on a road going truck. The swept volume of the MC chambers should be directly proportional to the swept volume of the brake caliper pistons so I am guessing (and will be happy to be corrected) that this will be a fair bit different on a 4 port MC compared to a 3 port one??? Or maybe not. Depends I guess on what the actual pipe configuration is on each. Those early systems had twin pipes to each front caliper so you need to workout how maany pistons are being moved by each MC chamber. If it is infact the same then you might be OK...... Quote Link to comment Share on other sites More sharing options...
Maverik Posted June 12, 2012 Author Share Posted June 12, 2012 I see what you're saying, the physical dimensions of the whole unit from the outside are identical to the removed unit, wether its an early split system or not you're only talking about a slight volume change due to pipework lengths. I think i've convinced myself its ok, but i might pull the master apart to check the internals compared to the old one. Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted June 12, 2012 Share Posted June 12, 2012 Hopefully Western will see this post and post up a schematic of the 4 port system compared to the 3 port one and we can work out which ports are powering which pistons. Should give an indication of whether they are approximately the same. Quote Link to comment Share on other sites More sharing options...
Maverik Posted June 12, 2012 Author Share Posted June 12, 2012 Hopefully Western will see this post and post up a schematic of the 4 port system compared to the 3 port one and we can work out which ports are powering which pistons. Should give an indication of whether they are approximately the same. Hmm good call, i'll have a flick of the manual later this evening see if that highlights anything. tbh, i might juts pop it in and see what happens, thankfully its one of the easier bits of a truck to remove/replace. - I do have a re-build kit for the old cylinder, but a bit short on time juts now. Quote Link to comment Share on other sites More sharing options...
western Posted June 12, 2012 Share Posted June 12, 2012 someone call Disco 1 front brake pipes no abs http://www.numcat.ru/landrover/p/32/45432/ & http://www.numcat.ru/landrover/p/32/45433/ rear no abs http://www.numcat.ru/landrover/p/32/45435/ master cylinder no abs but doesn't show all the ports http://www.brit-car.co.uk/product.php?xProd=92383 or http://www.carpartsdiscount.com/auto/parts/91/land_rover/range_rover/brake_master_cylinder/brake_master_cylinder.html?3593=121430 Quote Link to comment Share on other sites More sharing options...
Maverik Posted June 13, 2012 Author Share Posted June 13, 2012 Cheers Ralph. I had another look at it last night, other than the extra 2 ports I think its the same unit, my plan is to blank off the 2 unused ports and try it. I'll report back once its plumbed in, see how it feels. Mav Quote Link to comment Share on other sites More sharing options...
Maverik Posted June 17, 2012 Author Share Posted June 17, 2012 well put the master cyclinder in with the two extra ports blanked off with two blled nipples... I have brakes!!! after a lot of pumping, all 4 wheels bled out pretty well, but front right had a lot of air in the oil, to the extent that the oil was white... will bleed it again after I've let is settle, but even now if feel pretty good. Now got the discs to change out amongst a bit more welding... Mav Quote Link to comment Share on other sites More sharing options...
asilva Posted October 25, 2017 Share Posted October 25, 2017 Hi Maverik. I know that is a very long time since your post but I have a problem. I need to replace my master cylinder but TRW no longer produce them and I already try bearmarch but they don't work. So I remember that I can fit the old model the ntc4991 from TRW (still available) and blank the two extra ports. Did your adaption of the NTC4991 (blank of the two port) worked ok? What was the result in the long run? Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 26, 2017 Author Share Posted October 26, 2017 Yup, worked a treat and is still installed on the vehicle and hasn't had any problem what so over. Quote Link to comment Share on other sites More sharing options...
asilva Posted October 30, 2017 Share Posted October 30, 2017 Hi Maverik. Thanks for your feedback. Can I ask you if the brake power is good. Do you used the normal brake caliper bleed screws (RTC1526), did they blanked the ports without any problems? Cheers. Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 31, 2017 Author Share Posted October 31, 2017 Yeah braking is as what is should be, pretty firm as normal. yes RTC1526 will do it, thats standard metric land rover bleed nipple. If you where uncomfortable with bleed nipples you could quite easily pick up some blank ports too. But I had some spare nipples to hand so I used them. Quote Link to comment Share on other sites More sharing options...
asilva Posted October 31, 2017 Share Posted October 31, 2017 Thanks. I will try in the next couple of weeks... and see how it goes... Cheers. Quote Link to comment Share on other sites More sharing options...
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