can't bleed brakes-- passenger side fine, driver's side just air

[BerniniCaCO3]

OK this is NOT on a grand marquis. But I hang out on this forum mostly

I have a 1989 mercury tracer/ it's kindof a 1989 mazda 323, with the 1.6l fwd drivetrain. 95% of the parts are shared.
Just in case I leave out something important:

last winter the brake pedal would go to the floor, then recover and work. This happened a dozen times. No change in fluid level.
It's summertime now and I'm in the mood for car repair.
I swapped the master cylinder. It has two lines that go from it to the metering valve that is located 15" away on the firewall (unlike our boxes, where this is integral to the MC).
I also swapped 2 sections of line that went from the metering valve to the rear drums-- these lines had been cut in two, we replaced the longer sections 2 years ago, now the prior repair that went up the firewall was looking bad.
I don't know how to bench bleed a master cylinder and I don't think it necessary?
I filled up the MC, had a friend pumping the pedal the good ol' fashioned way, beginning with the RR.
I got fluid after a couple minutes, then I found a leak in one of the repaired lines. I'm still not good with flaring...
I bought 2 new pre-flared sections and fitted them correctly.
Now I tried again. RR works, no leak. LR takes friggin forever. And more forever. I try siphoning... I get a little, but no continuous flow.
Then I try the RF. Works, quickly.
Then I try the LF. Same story as LR... 10 minutes of pumping, plenty of splutters of air, but no real fluid!
The whole left side is FUBAR somehow.
When I checked the front pads, they seem evenly worn left to right.
When I disconnected the 2 lines that go from the MC to the metering valve, and had my friend step on the pedal, fluid DID come out of the MC from both ports.

Logical says to look at what *I* did and what might cause this... i replaced 2 sections of line to the LR and RR, and I replaced the MC. Could the new MC be bad somehow?
Or was the proportioning valve bad for some time, and this inability to bleed the brakes on the left side is only the most obvious manifestation, where it might not have been obvious while I was driving the car...?
I'm really confused, and really frustrated, and I needed to be driving this car 5 days ago. Bleeding brakes should not be this hard or this weird.

IS the proportioning valve bad? If so, I need to start calling junkyards RIGHT NOW to have any hope of not biking 20 miles to work in a few days. Couldn't find an aftermarket.
Is there something else I overlooked? One guy said to have the MC bench bled. I don't know that that makes sense, would not bench bleeding cause just the left side to just pump air? ...and before I walk 2 miles to the parts store to get the tools and re-R&R the mc I'd like to be sure that that could even be a possibility.


thanks for the help!
-Bernard

[slack]

Are you getting flow out of all ports from the proportioning valve? Maybe one of the ports isn't flowing. I say follow the lines until you find the spot where the brake fluid stops flowing. Other than that all I can think of is maybe there's a leak you're not seeing?

[gadget73]

Does this by chance use a "dual diagnonal" plumbing arrangement? I don't know Mazda at all, but I know VW used that crap. Rather than a front and rear circuit, it had one circuit that ran the front left and the right rear, while the other ran the front right and the left rear. It kind of sounds like you have that.

Anyway, bench bleeding the master cylinder is done without the lines hooked up. If one side is working, I'd leave that be and do the other one. If it will not bleed, its very possible that yours is shot.

http://youtu.be/kEPXgDGU6_0

you can do this with it mounted on the vehicle. Functionally it doesn't really matter if its bolted to a firewall or stuck in a vise.

[BerniniCaCO3]

Hey!
Sorry I took so long to get back on. Didn't have internet until now.

This was a frustrating one. So first I think that there must be SOME leak that's drawing in air, right? And I go and re-replace some lines that looked possibly bad.
I remove the lines to the mc, and pump just it. fluid out of both ports, a little more flow out of the one that's closer to the firewall, but hey it's first in line.
Then I buy a $45 hand held vacuum bleeder. Works nice, but left side, air and fluid air and fluid.

Finally I figure, well, what did I do? I replaced the mc and 2 lines, now I'm getting air. so it has to be something with that. I re-replaced the two lines, and so now I go and re-replace the new mc (sadly much more expensive in town than off rockauto).
It worked fine.

The system was split left-right (weird, right?) the front port on the mc goes to the metering valve where it then goes the lf and lr, and the rear port on the mc goes to the rf and rr.
The front port on the new mc was sucking in air with every pump, so I got fluid, I saw fluid coming out of it-- but it was pumping air along with it, every time.

So yup, you called it, bad new mc. I hate bad new parts Last one was dropping the fuel tank twice and spending an hour scratching my head over a new fuel pump that worked 5 seconds then stopped working (no, the wiring was perfect, it was the pump).

[GM_Guy]

Get used to it. In the ever lasting quest for cheapness, the end user is tasked with also doing quality control checks.

Alex.

[Toploader]

Wanna cry??? try getting quality points, cond, caps etc on cars so needing............GARBAGE...........point surface is sheet and the rubbing blocks wear down almost over-night........I am thankful I stock-piled ignition parts over 40 yrs ago, but the stock is getting low, as is the hope of the old car continuing to be as she should.

Get used to it. In the ever lasting quest for cheapness, the end user is tasked with also doing quality control checks.

Alex.

[gadget73]

Pertronix ignitor. I did that to my VW and the emergency backup set of points that I kept in the glovebox went with the car when I sold it for parts. By far the best upgrade I ever did to that thing.

[Toploader]

Not good for dual breaker Studebaker cars, again do not ask me how I know.......if that module craps out the only thing that you will do is call for the hook.......with points I can be on the road in 20 minutes.......I carry everything in the trunk.......including dwell meter and remote starter.

Pertronix ignitor. I did that to my VW and the emergency backup set of points that I kept in the glovebox went with the car when I sold it for parts. By far the best upgrade I ever did to that thing.

[gadget73]

oh, its got one of those Mallory double bubble things ? My granddad had a boat with a Cheesler 383 and one of those messes.


The Pertronix modules drop in place of the points. If it dies, you can swap back to the points in the time it would take to change a set, or at least thats how it was on the Bosch distributor. The magnet wheel slipped over the breaker point cam, and the module itself mounted to the hole in the plate that the points mounted to. The only difference was there were 2 wires coming out of the hole instead of one, one to each side of the coil.

[BerniniCaCO3]

On this same car, when bleeding brakes, I had the LR wheel cylinder fracture when I tightened the bleeder screw.
This is a new chinese wheel cylinder we installed 20 months ago. I didn't overtighten it. The screw didn't come close to breaking (like they usually do). Instead the cast iron housing just split (bad cast).
*sigh*

The tracer is done now though.
Wrapping up the colony park now.

[GM_Guy]

Then convert your stude to a single breaker setup. From what I remember the delco style distributor isn't that difficult to get.

Alex.