Series 3 Brake servo - LWB into SWB

Some time ago I got a brake servo and pedal assembly from a dual line LWB Landy and fitted in my SWB, which has a single line brake system. (It was refurbished before fitting).

I am now starting to wonder if the servo is compatible with a single line system and whether I need to replace it.

The brakes aren't working at present as I have replaced the brake lines and there is no fluid in the system.

Any help would be appreciated.

We need much more info. If you fit a dual circuit master I'm assuming you converted the brake circuits to dual circuit? If not stop now and get help.

Hi Rob - I haven't converted the brakes to dual circuit and that was why I started having second thoughts about using the LWB servo. If there is a problem now is the time to replace it with the correct one.

The best course of action would be to repipe the brakes to make it give dual line, assuming the servo and MC are in good order.

Col

Hi Col - all the brake lines and the brake master cylinder are new and the servo has been refurbished. I didn't want to run dual lines now that I have replaced everything so if the servo isn't compatible it would be easier to fit one that is.

88SWaB said:

Hi Col - all the brake lines and the brake master cylinder are new and the servo has been refurbished. I didn't want to run dual lines now that I have replaced everything so if the servo isn't compatible it would be easier to fit one that is.

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OK you did the right thing to stop. You have to do some research, start with Terri-annes expedition site and read the brakes section. Do some googling.
You have a choice to make and you need to be sure about which route you take:
1 std brakes, no servo - single line. simple and will work
2 dual line with later master cylinder and servo with SWB brakes you have the parts and it will work as the LWB master has same size front and read pistons
3 dual line with servo and LWB brakes will work well, but its a lot of work to swap the front brakes over as the back plates are getting rare.

Is it diesel or petrol? If petrol the servo is simple, if diesel you may need a vacuum pump, flap valve or tank. Mine has a vac pump.
Its not a big job to split the brakes circuit into 2 and pipe to the dual master, that's how my LWB has been done. Take time getting this right, its brakes.

Thanks Rob for your advice it is appreciated. I will do as you say and check out Terri-annes expedition site and research through google. As you rightly point out, it's brakes. Got to get it right.

By the way it is Petrol.

The LWB dual master can be used, but it has different unions so you must get the right ones if you don't have them. Also which master connection goes to front or rear is different SWB to LWB so you need to be careful and do your research. If yours has two 3 way master its a simple mod to take one out and run the rear to one union on the master and the fronts to the other via one of the 3 way connectors. If its got a single 4 way its better to take it out and get a 3 way.

I have had a quick look at the Terri-anne website and it has very comprehensive section on brake servo's. It is going to take me a while to go through it all. Thanks again for your help.

I'm assuming you have a standard 10" SWB setup. If you already have the correct SWB single line master for fitting to the servo you are good to go. If you want to upgrade to a dual line system then make sure you get the smaller SWB master, the LWB one is to large and will give you a heavy pedal.

Hi CK - I have standard 10" SWB set up and I 'believe' I have the correct MC for a brake servo. I bought the MC some time ago and I will to check it.

That is one of the pitfalls of a long term project you sometimes forget things.

Thanks for the reply.

I can confirm that the master cylinder I have fitted is for a single line servo, part number 569339.

I think that's probably a LWB MC, it will work but its unnecessarily large as normally it would have to deal with TLS front brakes. There isn't much documentation about servo assisted SLS SWB brakes. When I was digging around I managed to find out that the lightweight was fitted with a servo and a dual line MC suitable for SLS brakes so this is the way I went but with 11" SLS on the front.

I believe you are right about the MC as 569339 is listed in the parts manual under 'Master Cylinder and Servo 109in'. It appears that I need to decide what to do next. Thanks for your replies.

I have servo fitted to single line 10 brakes with this master cylinder to my SWB.
Part used was Bearmach brake master cylinder BR3022

Thank you for the picture showing your set up which looks almost identical to mine. Do you think the two MC's (BR3022 & 569339) are the same? They certainly look alike and if you do a search on the Bearmach website for 569339 two MC's come up, BR3022 (with photo) and the Girling one (569339-G, photo coming). As the Girling one is £311.39 it is possible that BR3022 is the cheaper alternative.

I need to find out if the Bearmach BR3022 is the same as Britpart 569339, which I have. Fingers crossed.

Its a very long time since I did any digging on the subject but I think I came to the conclusion that Land Rover never fitted a servo to any domestic single leading shoe SWB models. There is some anecdotal evidence that some export models were fitted with servo assisted SLS brakes but they tended to have the dual line master cylinder. After I found out that lightweights had an dual line SLS option I never bothered digging any deeper into single line master cylinder option but it looks like you probably have the only option available, Looks like Blackburn is running the same LWB master cylinder as you, maybe he would be best placed to comment on its suitability.

Over the last couple of days I have arrived at the same conclusion as you CK and agree that Blackburn is best placed to comment on the set up. One thing that I was looking for was confirmation that the set up was safe. As Blackburn has been running with the same set up I assume that it is.

My brakes are working fine have 200DI in and upgraded brakes as I can easily do 70mph max seen on speed app was 84mph so was going to go twin leadiing shoe set up but when I heard they are poor in reverse was not suitable for the trialling I was doing so went for this option.
They are standard part for early servo on 109 station wagon and six cylinder.
Also listed in the optional parts section as suitable for 88 and 109.
Have you actually put fluid in and bled the system?
When I fitted mine I had to adjust the pushrod coming from servo to master a little bit to ensure piston was coming all the way back in master cylinder.
Edit if you look in this post Sam88 has same set up
https://www.landyzone.co.uk/land-rover/1976-series-3-rebuild.202564/
I know him and it was his advice that got me fitting what I have.

No fluid in the system yet. How do you adjust the pushrod?

Impressive speed which I doubt I will achieve in a standard SWB 2 1/4 Petrol.