help diagnose these symptoms

[rbonnett]

Wow. I would have thought a '73 would have dual circuits. I assume it was a UK difference, cuz I can't imagine anyone converting from dual to single circuit. Looks like that is the MC you want to exchange for. The big difference for you is just one circuit out of the MC to bleed on the bench.
People do convert from the older single to dual circuit systems - never done it. Maybe someone else can provide some detials of that. One big diff is a valve fitting that cuts out one circuit if it loses pressure.

[LaneRover]

See what ya get from listening to me! Sorry if I helped lead ya down the wrong path!

To convert to a dual system You need to separate the front brakes from the rear. The factory did this on the right side on the frame near the oil filter (if my memory serves me correctly) There is a part that does that and its name escapes me. You'll also have to run an additional line from the brake dual MC to that splitter thingy. I believe you can leave the rest of the system alone.

Brent

[Sputnicker]

I'm also very surprised to see a single-circuit master on a car of that vintage. Dual circuits have been required in the US since 1968 and I thought most other countries had also adopted them by then (the Swedes were the first to use them). It may be some kind of kluge by a previous owner.

The single-circuit master that you provided the link for is definitely not correct - note that the 2-bolt flange is 90 degrees different (vertical instead of horizontal) and will not bolt up to the servo. I guess your only alternatives are to try to find a replacement for what you have (start calling suppliers, or looking at British web-sites), or converting to a dual system, which will be a pain, but the parts are available and it will be a safer vehicle when you're done. There's also the risk that it may not pass a safety inspection (by a very observant inspector) in some states with single-circuit brakes.

On the exhaust, if it's leaking at the manifold, you have no choice but to start unbolting things and having a look. Use some penetrating fluid, bend back the rusty lock tabs and go for it. The cast iron on the manifold is very thick, so they can be quite rusty on the outside and still work perfectly. If there aren't any cracks or other defects, it should be fine. When you order the manifold gasket, you may want to also get the flange gasket for the bottom (just in case) and new nuts, bolts/studs and washers. You are likely to break and/or mangle a few.

Good luck.

[SafeAirOne]

Count those lines first! My 1973 UK-spec 109 also has the single circuit master cylinder--the exact same one you pictured. I won't mention the copper brake line used throughout the entire system...

Sputnicker is right, you need to make sure you get the single-circuit MC with horizontal mounting tabs (where it fastens to the brake booster (servo). I've replaced my MC in the past so the MC is certainly available, though I can't recall where I got mine. I'm willing to bet that our hosts have them--Just describe it accurately to them.

[NickDawson]

Count those lines first! My 1973 UK-spec 109 also has the single circuit master cylinder--the exact same one you pictured. I won't mention the copper brake line used throughout the entire system...

The green bible clearly shows single and dual systems. So I'm guessing it was either vintage or country specific. I'm in a debate between conversion and just replacing with another single... as the issues pile up I have visions of my truck not running for a year... I'd kinda like to just get it fixed.

Sputnicker thanks for the info on the exhaust... My number one order of business is getting the breaks working and the carb tuned, but its clear that I'll have to do something about the leak before it will pass inspection, not trilled about it, but glad to know that the parts might be salvageable.
______________
edited to add:
Guess who is going to a dual circuit break system? Our awesome hosts are helping by making some lines and as always Steve has made the conversion sound easy

The plan is to run a new line to the back junction from the new master. Then I'll run a short piece of new line from the MC down to a 3 way junction that splits the existing front front lines.
It actually does sound easy enough.


In case anyone else ever runs into this - apparently there was a factor option for the early III 88s where you could order a power assisted single circuit break system. Not sure why someone would chose that over the dual system, but there it is. That MC is not something that RN stocks.

[SafeAirOne]

edited to add:
The plan is to run a new line to the back junction from the new master. Then I'll run a short piece of new line from the MC down to a 3 way junction that splits the existing front front lines.
It actually does sound easy enough.

Easy and much safer. Good choice.

[kevkon]

Definitely bleed the whole system, I'd recommend contacting http://speedbleeder.zoovy.com/ to see if their speed bleeders are available for the rover. Definitely makes brake bleeding a snap with one person.
Have you confirmed that the ignition and cam timing is correct?

[NickDawson]

Definitely bleed the whole system, I'd recommend contacting http://speedbleeder.zoovy.com/ to see if their speed bleeders are available for the rover. Definitely makes brake bleeding a snap with one person.
Have you confirmed that the ignition and cam timing is correct?

Those speed bleeders look very slick. Still not sure I fully understand the entire process enough to warrant adding something new, I plan to enlist the wife to make it a 2 person job. She can pump the breaks and I'll look for bubble free fluid.

As for timing - no, I haven't had a chance to think about that. All signs point to the carb at this point, I'm going to take it off tonight and make sure the float isn't stuck.

[scott]

easy cheap one man bleeders

if you're flushing start with a short hose off the bleeder valve into a quart jar, pump until you've run your resivor dry at least three times for the first (left rear on an 88 lhd) then discard the contents of jar. replace short hose with a long enough one to reach from the bleeder valve to the resi. clip the end of the hose into the resi so that its below the the surface. get a beer. sit behind the wheel and start pumping. pump until you see no more air go through the hose (oh year use clear hose) that runs right past you. repeat for each wheel. depending on how fast you drink you may need to wait a while before testing

[kevkon]

The speed bleeders work well. Basically it's a check valve so you don't have to keep loosening and tightening the bleeder. You would be surprised at how little air in the system is required for there to be excessive pedal movement. Improper brake adjustment will also give you the long pedal travel.
You really should check the timing before any carb adjusting because you may end up getting further away from where you want to be.

[NickDawson]

get a beer.

I like this plan!

Do I need to actually clamp off the other 3 lines, or is simply opening the bleeder valve on one break cylinder at a time sufficient?

[scott]

I like this plan!

Do I need to actually clamp off the other 3 lines, or is simply opening the bleeder valve on one break cylinder at a time sufficient?

leave all bleeder valves closed except one. start with the one furthest from the mc and work towards the closest. use break line legnth not straight line. on my 88 lhd it is lr, rr, lf then rf.

after putting on the clear tube open the valve and leave it open. don't forget to open the beer. after the little air bubbles stop pass'n you by stop pump'n and you can leasurly go and closed the bleeder valve, leave the one end of the tube in the rezi and move the other end to the next valve, hook it up, open the valve, check rezi level, get another beer and go back to pump'n the brake pedal. this works for the clutch too but it's harder to kill a six pack.

[bmohan55]

pm'ed ya

[NickDawson]

File this under the: "hows it work" section rather than "hes just crazy enough to risk his life on something stupid" section...

Could a dual circuit master cylinder be used in a single circut system, by either capping off the 2nd outlet our using a Y fitting?

Also, along the lines of Kevkon's suggestion - whats the best way to check timing? I see $30 timing lights on Amazon... but not sure how that whole ignition system works.
edited to add: just found this awesome post from Jeff on using a timing light

http://www.roversnorth.com/forums/showthread.php?t=6298&highlight=timing+light

Seems like an easy thing to check

[kevkon]

It is easy to check Nick and if you don't want to buy a strobe light you can go to any repair shop and ask them to check it. This will tell you whether the timing is correct, whether the advance is working, and whether there is any indication of a worn timing chain or gears. I'd start here before playing with the carb, especially on an older vehicle.