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Thread: Upgrading Series 2A Short Wheel Base to Series 3 Long Wheel Base Brakes

  1. #1
    Lionelgee is offline YarnMaster Silver Subscriber
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    Upgrading Series 2A Short Wheel Base to Series 3 Long Wheel Base Brakes

    Hello All,

    What diameter brake pipe should I ask for to suit a six cylinder 109 Series 3 brake system?

    Can brake junction blocks be cleaned and reused?

    My late model Series 2A Shortie has had its brakes upgraded by a previous owner - well sort of. The drums, backing plate and wheel cylinders were upgraded from a 2A short wheel base to a Series 2A or Series 3 four cylinder 2.25 109's brakes. The system was also improved by adding a brake booster fed by a Japanese alternator with a vacuum pump. This was done without upgrading the brake pipe diameter.

    After continued problems with the current arrangement I want to go up one step further with the brake upgrade. I am thinking about upgrading to a 109 inch Series 3 six cylinder brake circuit. I have a number of 109 Series 3 which were originally six cylinder motors that I can take parts off.

    New wheel cylinders, brake pipe and brake shoes will be fitted. Hopefully during this process the current issue with the brakes will be eliminated.

    Kind regards
    Lionel

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    Brake pipes are the same diameter for late Series I and Series II, IIa,III, LWB or SWB.

    Not sure what you mean by a 'brake junction block', just one of the brass connectors that joins 3 or 4 pipes together ? If so there is no reason not to re-use as long as the threads aren't damaged.

    Main difference with the 6-cylinder brake system is different front wheel cylinder, wider drums & brake shoes.

    If yours already has LWB drums, backplates & shoes there is no benefit in changing to a different set of parts unless you're after the wider 6-cylinder fronts. Wallit has LWB brakes with a Series III booster and you can lock up the wheels.
    What booster does you current system use ?



    Colin
    '56 Series 1 with homemade welder
    '65 Series IIa Dormobile
    '70 SIIa GS
    '76 SIII 88" (Isuzu C240)
    '81 SIII FFR
    '95 Defender Tanami
    '58 Series II (sold)
    Motorcycles :-
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  3. #3
    JDNSW's Avatar
    JDNSW is online now RoverLord Silver Subscriber
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    Upgrading brakes? The question is, what do you mean by upgrading?

    There are several different (but somewhat interrelated) things that you could mean, so looking at them separately:-

    1. Pedal Force required. This depends on only three factors:-
    a) Mechanical advantage - pedal leverage (fixed unless you get really fancy), hydraulic advantage (master and wheel cylinder diameters, number of wheel cylinders), drum diameter
    b) Self servo action - depends on one or two leading shoes, lining material.
    c) Whether a vacuum servo is fitted and its size.

    2. Maximum braking effect. Depends on proper proportioning of braking effort between front and rear. Braking "upgrades" can easily affect the compromise made by the designers. The danger is in either making the front braking much better so that when loaded it is easy to lock the front wheels without even getting maximum braking on the rear, or worse, having the rear wheels lock when unloaded before maximum braking is achieved on the front.

    3. Fade resistance. This is a serious issue with any drum brakes and even more so with two leading shoe designs. Depends almost entirely on the area of the drum surface, which is where larger diameter and width come to the fore.

    4. Water resistance. Forget solving this with any drum brakes!

    5. Low maintenance - use quality parts and avoid using the brakes as much as possible, change the fluid regularly, especially if you live on the coast, and use the vehicle regularly.
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

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    Quote Originally Posted by Lionelgee View Post
    Hello All,

    What diameter brake pipe should I ask for to suit a six cylinder 109 Series 3 brake system?

    Can brake junction blocks be cleaned and reused?

    My late model Series 2A Shortie has had its brakes upgraded by a previous owner - well sort of. The drums, backing plate and wheel cylinders were upgraded from a 2A short wheel base to a Series 2A or Series 3 four cylinder 2.25 109's brakes. The system was also improved by adding a brake booster fed by a Japanese alternator with a vacuum pump. This was done without upgrading the brake pipe diameter.

    After continued problems with the current arrangement I want to go up one step further with the brake upgrade. I am thinking about upgrading to a 109 inch Series 3 six cylinder brake circuit. I have a number of 109 Series 3 which were originally six cylinder motors that I can take parts off.

    New wheel cylinders, brake pipe and brake shoes will be fitted. Hopefully during this process the current issue with the brakes will be eliminated.

    Kind regards
    Lionel
    The three way unions (which I'm assuming is what you mean by junctions) can be reused. Just give them a clean and make sure the threads aren't damaged or they'll leak.

    You really need* to keep the braking system consistent from the master cylinder to the brake drums - otherwise you need* an engineer to approve the mods. So if you have S3 109 stuff at the backing plates you should use an S3 109 master cylinder and booster - this way everything works as it should.

    (*need = really means 'should' because in the end it's up to you. If you mix and match it may fall foul of the legal requirements though.)

    My SIIA shorty has its original backing plate stuff (shoes, cyls, drums) but a booster and master cylinder from an XC Falcon - god knows why, that's how it was when I got it. The engineer that approved the holden conversion for me also checked, tested and approved this brake mod so it's now kosher, but I will change it out for a S3 boosted dual circuit system when this master cylinder dies. Having these hybrid systems is just inviting problems later on in my opinion, and a shorty SIIA stops just fine with its standard brakes.

    As Gromit said the lines are all the same diameter - 3/16".

    Cheers,

    Adam

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    Quote Originally Posted by akelly View Post
    You really need* to keep the braking system consistent from the master cylinder to the brake drums - otherwise you need* an engineer to approve the mods. So if you have S3 109 stuff at the backing plates you should use an S3 109 master cylinder and booster - this way everything works as it should.

    (*need = really means 'should' because in the end it's up to you. If you mix and match it may fall foul of the legal requirements though.)
    I wonder if anyone has ever done that ? Unlikely a roady tester would even spot the changes from SWB to LWB brakes.
    Adding a booster shouldn't be an issue, especially if it was from another model Land Rover or an aftermarket in-line booster which was a common addition.

    From Lionel's description it already has LWB brakes, the only advantage of switching to a 6-cylinder system would be the wider front drums. Possibly overkill on a shorty.


    Colin
    '56 Series 1 with homemade welder
    '65 Series IIa Dormobile
    '70 SIIa GS
    '76 SIII 88" (Isuzu C240)
    '81 SIII FFR
    '95 Defender Tanami
    '58 Series II (sold)
    Motorcycles :-
    Vincent Rapide, Panther M100, Norton BIG4, Electra & Navigator, Matchless G80C

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    Quote Originally Posted by gromit View Post
    I wonder if anyone has ever done that ? Unlikely a roady tester would even spot the changes from SWB to LWB brakes.
    Adding a booster shouldn't be an issue, especially if it was from another model Land Rover or an aftermarket in-line booster which was a common addition.

    From Lionel's description it already has LWB brakes, the only advantage of switching to a 6-cylinder system would be the wider front drums. Possibly overkill on a shorty.


    Colin
    I definitely wouldn't bother going to 6 cyl brakes, no advantage to be had in a shorty. I've definitely seen IIA's with III boosted brake systems though.

  7. #7
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    Quote Originally Posted by akelly View Post
    I definitely wouldn't bother going to 6 cyl brakes, no advantage to be had in a shorty. I've definitely seen IIA's with III boosted brake systems though.
    My Series III shorty with servo assisted LWB brakes will smoke the tyres Isuzu C240 powered Series 3


    Colin
    '56 Series 1 with homemade welder
    '65 Series IIa Dormobile
    '70 SIIa GS
    '76 SIII 88" (Isuzu C240)
    '81 SIII FFR
    '95 Defender Tanami
    '58 Series II (sold)
    Motorcycles :-
    Vincent Rapide, Panther M100, Norton BIG4, Electra & Navigator, Matchless G80C

  8. #8
    JDNSW's Avatar
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    Quote Originally Posted by akelly View Post
    I definitely wouldn't bother going to 6 cyl brakes, no advantage to be had in a shorty. I've definitely seen IIA's with III boosted brake systems though.
    I fitted a VH44 remote booster to my Series 2 shortie in 1964 (and was very happy with the results), but I have not felt the need to fit a booster to my 2a lwb, thanks, I believe, to the two leading shoe design of the front brakes.
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

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