Series 3 Single line brakes or dual line?

hello,
i'm new to all this, and need some help to understand if my series 3 (109") has a dual line or single line brakeing system. it has a dual line master cylinder, but then going into a single line shortly after. see attached photo.

Depends on the year of manufacture whether duel or single line. On your truck the T piece would have been fitted down on the chassis and would split the feed to the front brakes, Second line would travel to the rear and split at T on the axle. Looks like something of a cobble up and need sorting out.

How many outlets in the master cylinder?

Built in 1977, it has two outlets in the master, then t's up into one, which as far as I can see is pointless....

Where does the second line go?
(Hope not into that T piece)

Well yes it does, which makes me think that it is a single line, but who ever had it before put the wrong master on it, and put both lines going into one?

you Would need to have a compensater between the front/rear lines
You convert this easily

Looks like a duel MC made to fit a single line . Where does the single line go to? Does it go into another connector feeding the from axle and rear? Mine (Series 3 1981) is duel brakes and both pipes go from the MC down to the chassis into a PDWA valve. From here it splits to the front and rear.

https://www.landroverweb.com/landrover/pdf-land-rover-manuals-part-catalogue/

Try the link above to try and identify what you have.

Rich

Doesn't look like a standard Land Rover Series servo to me so might not be the correct master cylinder. Clearly a bit of a lash up, might be a master cylinder for disc / drum combination, the outputs might have been linked together to rebalance the system, all Series drum tandem master cylinders are matched bore size, some disc / drum master cylinders have mixed bore sizes.

For your year Single line is normal the dual line came in 1980 , I think you’re right in that it’s had the dual master cylinder fitted into the single system
My 84 88 has the pressure sensing valve which lights a warning lamp in middle of dash if pipes lose pressure
What’s the braking like on yours

Thanks for all the responses, looking closer it is obvious that they have chopped out some bodywork to fit the larger servo in.
The brakes don't work at all, the pedal is solid, hence looking at the servo to replace it.

Is the servo getting a good vacuum, is the hose connected to the diesel inlet manifold
There should be a butterfly valve in there which is closed when throttle off they need setting up
Has yours got the vacuum reservoir bottle
Is the one way valve in servo working ok
With engine running take pipe off from servo end and check suction
servos don’t go wrong often don’t buy just yet

At the other end is the wheel cylinders and shoes have these been checked
When was it last MOTed
Even with servo not working properly there should be some braking, can jack up, press brake and try to turn wheels with helper

I would re pipe that ASAP. Check the master cylinder part - it should have some numbers on. If you're lucky its a LWB dual circuit in whcih case a few brake pipes and you'll have a dual cicuit brake system. If its both pipes into 1 (as its looks) the pedal will be rock hard as its 2 x the piston area. Since the pipes will have to sorted better to start with that, then set the pedal / servo gap etc. Post a pic of the side of the master cylinder so we can see the connections, if one union is bigger than the other there's a good chance it the correct dual master. If it is just follow the pipe down to where it splits front and back and take the union out and connect front to rear on master and rear to front. Its a bit of a faff if the line across to the near side is after the union, you'll have to re run that as there's a single line to the rear but one each side to the front (probably under the bell housing), you can re-use the Tee union to split the front line. If you've not run brakes before watch a few you tube videos, indentify the threads (UNF vs metric), buy a few unions (dirt cheap) some 5mm / 3/16 (its all the same) cupronickle pipe (quite cheap) and a set of in-situe benders (save loads of time and money). Practice a few then good to go! Note that the metric and UNF flares are not the same so make sure the tool does both. Expect to find a dogs breakfast of metric and UNF and pick one then stay with it. I found UNF easier to get the brake cylinders and it was right for the year.

Taken the pipe off, good suction to the servo, so either the one way valve has gone or the servo gone. Brakes work To a certain extent, but you have to drive it like the QE2 and brake 3 miles before you want to stop whilst standing on the brake pedal.
The master cylinder is clearly not right as one line comes form the opposite side to the other. Rather than the same side.

I'm beginning to think it is probably best to purchase a new servo and new single line master, and redo it completely

I think its the wise decision. Personally I would go with the tandem master cylinder, you already have a bit of plumbing to do, its not a lot more effort to split it into two circuits.

rob1miles said:

If its both pipes into 1 (as its looks) the pedal will be rock hard as its 2 x the piston area.

Click to expand...

so could this be the reason for hard pedal rather than dodgy servo
Normal test is to press brake pedal start engine see if pedal sinks a bit if it does servo working

Tested that, there isn't any difference to the brake pedal if the engine is on or off...

You maybe pushing fluid against the second part of the circuit which makes the pedal feel hard.

So the 2 connections from the MS go to the T piece, where do they split again for the front & rear ?
(A complete re plumb of the brake lines would also be better)