ejparrott Posted October 18, 2011 Share Posted October 18, 2011 My 109's been converted to servo dual line brakes by the PO, never got bled properly and the res split so after a bit of a faff, I've now got a new master and res. She's got 11" TLS front brakes, 10", sure they're not 11", SLS rear brakes, so thats 2 cylinders at front, 1 cylinder at rear. She's got a PDWA valve in, it could be stuck I dont know, I'm going to put a test lamp on it at the weekend and see if it comes on. I found a web page last week that listed a whole range of chassis number and years versus what master cylinder, brakes and wheelbase - now I cant find it. Its not expeditionlandrover and its not nickslandrover, unless its tucked somewhere I've missed. Its not Glencoynes either. Anyone? What I'm trying to do is confirm whether I should be putting the front brakes to the rear port on the master (closest the servo) and the rear brakes to the front port. I think it should be as the rear of the master has the larger piston for the extra 2 cylinders on the front, but the PO has put front to front, logical way. I've been doing a lot of googling of the last 2 days and I've got so many different views on front to front and front to back I dont now know for sure!! Its a NRC6096 master cylinder. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 18, 2011 Author Share Posted October 18, 2011 Further information: My 88 has the same master cylinder, also has 11" TLS front brakes, and deffinately 10" single culinder SLS rear brakes, and a PDWA valve which I believe to be working, or jammed in the middle where it does no harm. It appears that the master is plumbed front to front of PDWA, then rear brakes, and rear to rear of PDWA, then front brakes. The Master cylinder is found on page 1L08 of the Series 3 parts cat, and the plumbing seems to agree with the illustration on page 1L11 of same, which shows front to rear brakes and rear to front brakes. On the plumbing page, it does say 'July 1980 onwards', which would be right for my 88. However, there appears no mention of sates on my page of the master. Quote Link to comment Share on other sites More sharing options...
secondjeremy Posted October 18, 2011 Share Posted October 18, 2011 I think the difference between LWB 80 + and earlier dual master cylinders is really the use of metric fittings. be careful metric will screw into imperial loosely - which is obviously dangerous. What makes you think the 2 master cylinder pistons have different diameters? - its not a BMC MIni. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 18, 2011 Author Share Posted October 18, 2011 Deffinately metric, I've got 6g plug gauges for both, and 6h ring gauges for both. I'll see if I can find the articles I've been reading that say its different diameters. My 88 has the same master and same brake setup, as far as i am aware her original facory fitted. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 19, 2011 Author Share Posted October 19, 2011 Well according to expeditionlandrover.info "The 109 master cylinder is connected so that the tubing for the front brakes is connected to the larger diameter cylinder, located closest to the booster. The tubing for the rear brakes is connected to the front most cylinder." on Landrovernet.com I found "Duel line brakes have the front brakes at the rear of the master cylinder and the rear brakes at the front." However, another chap quoted the green bible as saying "Interestingly, the Land Rover Series 3 Repair Operation Manual states on page 70-1: “NOTE: On dual braking systems, the hydraulic fluid is divided into two compartments. On 88” models, the front compartment supplies the rear brakes and the rear compartment the front brakes; on 109” models, however, the reverse applies and the front compartment supplies the front brakes, and the rear compartment supplies the rear brakes. ...” Leaves me in a bit of a pickle now....dont know whether to copy the 88's which has the same brake setup, and which works extremely well, or whether to go with what the green bible says (havent checked my own yet) and plumb it the other way... Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 19, 2011 Share Posted October 19, 2011 Why not take it apart? The larger piston will go to the front brakes. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 19, 2011 Author Share Posted October 19, 2011 'cos its brand new, and according to the packaging at least, its got a 3 year warantee.....could dismantle the old one though I suppose, its the same and I need to to remove the broken pipe fitting anyway, then I'll service it as a spare..... Quote Link to comment Share on other sites More sharing options...
Gazzar Posted October 20, 2011 Share Posted October 20, 2011 Why not take it apart? The larger piston will go to the front brakes. I'm having a "thick" moment, but wouldn't the larger piston ALWAYS be the one closer to the mounting flange? On account of the milling machine thing only being able to drill from one end and the bigger boring bit cutting away everything in it's path? Unless, of course they drill in from the other side of the casting, which would be pointless, as it is easier to just run the pipes to the flange end. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 20, 2011 Author Share Posted October 20, 2011 You're right...but I'm also thinking dismantling the old one might put to bed the question of whether it truly has 2 different diameter pistons.....expeditionlandrover says it does, secondjeremy believes it doesnt...I have no idea! Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 20, 2011 Author Share Posted October 20, 2011 Well I started stripping it, and it appears to be one single bore, however there's a pin preventing the forward piston from coming out, and at the moment I cant see how to get it out. Off to google!! Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted October 20, 2011 Share Posted October 20, 2011 From the workshop manual: Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 21, 2011 Author Share Posted October 21, 2011 Thanks Retroanaconda, unfortunately thats the previous model dual line master to mine. I discovered that there is a little pin under the seals for the forward port of the resevoir, which is just dropped in from the top. You have to compress the forward spring and pull it out with pliers. Well according to expeditionlandrover.info "The 109 master cylinder is connected so that the tubing for the front brakes is connected to the larger diameter cylinder, located closest to the booster. The tubing for the rear brakes is connected to the front most cylinder." Well, I got it stripped, and in regard to this particular master cylinder, part number NRC6096, this statement is not accurate, it has one size bore right through, so diameter wise both pistons are the same. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 21, 2011 Author Share Posted October 21, 2011 Quote Link to comment Share on other sites More sharing options...
ejparrott Posted October 25, 2011 Author Share Posted October 25, 2011 Well I've been putting a lot of thought into this and I've decided I'm going to swap the plumbing so that the rear cylinder operates the front brakes, and the front cylinder the rear brakes. This is how my 88 is plumbed, and there's a gentleman on OLLR who has his 109 plumbed this way. The red herring of different size cylinders is out the window, and at the moment I cant see how the master will prevent loss of fluid or total lose of braking if one side goes. I cant tell for sure, but I believe there is movement in the rear cylinder (closest to servo) before either the spring operates the fron piston or the rear contacts it to operate the other brakes. That makes sense to me in as much as front brakes are supposed to operate before rears, IIRC. Both springs are quite powerful, and certainly wit no connections the spring at least is pushing the front piston. I'll have to see if I cang et a pressure gauge on both outlets and see whether one really does work before the other....rpoject for the winter me thinks. I'm also planning on removing the PDWA valve. Initially to investigate whether its working, how servicable it is, and whether or not it will seal off a broken line, with a view to maybe re-fitting next time The 109 has a full brake service, or when the 88 has its new chassis - then servicing the 88's ready for The 109's. Its entirely possible of course, that if it proves not to seal off a broken line, it'll never get re-fitted. Thanks for the help chaps, I'll let you know how it goes when its done. Quote Link to comment Share on other sites More sharing options...
secondjeremy Posted October 26, 2011 Share Posted October 26, 2011 The PDWA has both hydraulic circuits passing through it - with a shuttle valve which moves (and operates the light) if the pressure drops in one circuit. The theory is that if one circuit collapses it does not affect the operation of the good circuit. I does not affect the operation of the damaged circuit. There are 2 reasons for this - 1 being that the thing can only be centred by opening one circuit - so if this was not done then one circuit would not function, the other reason is that if there was a partial leak - you'd like the light to come on to inform you that you had a problem - but would like the benefit of whatever braking the damaged circuit could provide (which could be considerable) rather than having a light and no front brakes as the valve had decided that it was more important to put the light on than save your life. Makes sense to joint 2 separate circuits with a warning device doesn't it! Quote Link to comment Share on other sites More sharing options...
Snagger Posted October 31, 2011 Share Posted October 31, 2011 My 109's original braking system was set up with the rear (servo) end of the MC connected to the front brakes and the front end of the MC to the rear brakes. Looking at the sectional diagram, the void for the rear piston (occupied by the spring between the two pistons) appears to have much larger volume than the void between the second piston and the end of the cylinder. That suggests that the first piston should indeed operate the front brakes. Expedition Portal has some very good advice, but also has its limitations and inaccurate posts, just like any other forum. Sadly, LR's own manuals have inaccuracies too (I have been struggling with our Lightweight's engine as a result of just such a deficiency), so I'd ignore that quote from the Workshop Manual about the difference between 88 and 109 brakes; the 109's bigger rear brake cylinders will require more fluid than the 88's rear cylinders, but still not as much as the TLS dual front cylinders. My 109's brakes have a firm pedal and are very effective set up the way you plan. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted November 1, 2011 Author Share Posted November 1, 2011 Thanks Snagger! Unfortunatly, it took me the best part of 2 days to get the LaSalle headlining fitted up, so I never got chance to look at The 109's brakes, that and the light fading early. I'm going to try again next weekend, it being dark in the week when I finish work now Quote Link to comment Share on other sites More sharing options...
Snagger Posted November 1, 2011 Share Posted November 1, 2011 Just to give you the full specifics, my MC to PDWA valve lines are parallel. The line for the rear brakes comes from the (vehicle) front lower PDWA port, while the front brakes have a single line from the aft lower port crossing over the rear line and running to a T-piece on a small bracket attached to the upper end of the driver's side inboard bump-stop V-bracket, where it splits to run directly to each flexible hose. That was the scheme used in 1982 that I copied on my rebuild. Some other schemes have parallel lines from the PDWA valve to the front hoses, but I don't see any benefit in that. I have a La Salle head lining and it does a very neat job of lining the roof. I used camping roll-mat bonded to the original roof as insulation and sound deadening and will be adding draught excluder tape around the edges to stop a couple of rattles of the GRP lining against the roof's inner gutter channel. It all fitted well except for the alpine light surrounds, which are a bitch to fit. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted November 1, 2011 Author Share Posted November 1, 2011 Thats the same as my 88's plumbing, unfortunatly I'll have to cross the lines on the way to the PDWA as the chassis lines can't be swapped - they're not long enough. There's a chap on OLLR who's brakes are set up like that, he reports no problem. The roof does look nice now, but boy what a game fitting it! Quote Link to comment Share on other sites More sharing options...
Snagger Posted November 2, 2011 Share Posted November 2, 2011 Thats the same as my 88's plumbing, unfortunatly I'll have to cross the lines on the way to the PDWA as the chassis lines can't be swapped - they're not long enough. There's a chap on OLLR who's brakes are set up like that, he reports no problem. The roof does look nice now, but boy what a game fitting it! Crossing the brake lines before instead of after the PDWA valve will make no difference - the innards of the PDWA valve are essentially symmetrical and the hydraulic pressure in each system should be equal at all times. Just make sure the new pipes can't rub against each other where they cross over. If in doubt, slit a length of silicone or fuel hose to cover the brake line at the crossing point to prevent chafing from vibration. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted November 12, 2011 Author Share Posted November 12, 2011 Well, all the plumbing's back together today, front to rear brakes and rear to front brakes, and we've had a session bleeding them, but its no good at present. Part of the problem may be that my Gunson Easibleed has split its cap so I suspect its not pressurizing the fluid at all well. Additionally, 4 out of 8 adjusters are seized or rounded off, so I can't even be sure of proper adjustment. I'll have to go right through and do a complete overhaul of the system and then bleed it again, with a new cap for the easibleed. So as it stands, still unuseable Quote Link to comment Share on other sites More sharing options...
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