Newbie questions on wheel cylinder functionality [Update]

[DeadStang]

I'm working on my '69 Coupe by myself. It has 4-wheel manual drums and it's been awhile since the brake fluid has been flushed. So I've just done the water pump and still have it up on jack stands, so I thought I'd flush the brake lines.

I sucked all of the dark, yucky fluid out of the M/C and replaced with fresh.

I started with the R rear--I used a couple of red rubber urinary catheters fixed to a 35cc syringe and bled that line until the fluid was clear-ish, about 2 fills of the side of the M/C. I tried the same on the left rear, and get air/air/air. So I got my husbands Mighty-Vac thingy, thinking it would have better suction and I still only get air and a tiny dribble of fluid. I took the bleeder valve out and no fluid exsanguinated from the wheel cylinder. I would think fluid would come pouring out if all was well? So I sprayed brake clean in the valve, then air thru it, making sure it wasn't blocked, which it was not, and re-installed. I tried the Mighty-Vac again, with the same result.

I have a low tolerance for frustration, so I moved on the the right front and successfully bled that line with my urinary catheter and syringe.

Then I got the bright idea of pumping the brake pedal a bunch to maybe free up a chunk in the brake line to the left rear wheel. I've pumped the pedal a bunch of times and tried the Mighty-Vac over and over and still don't get but a drop or two of fluid. The pedal feels normal to me.

My questions are: (1) should fluid have poured from the cylinder when I removed the bleeder valve if everything was as it should be? (2) Since this didn't occur, does it sound like the brake line to this wheel is clogged? It outwardly "looks" OK with no obvious crimping or issues. (3) Or does this sound more like a wheel cylinder issue? The drum drags a little like they always do and "feels" normal to me; however, I have not removed the drum as I don't want to mess up the brake adjustment on this side and I suck at adjusting brakes. (4) Does anyone want to come to Oregon this evening and help my bleed the brakes using the pedal instead of this Micky Mouse Mighty-Vac or my syringe and tubing method? (lol)

Thanks!

 

[Midlife]

Re: Newbie questions on wheel cylinder functionality

Yeah, something's not right, that's for sure.

Can you break the connection from the brake line to the wheel cylinder? If you press the brake pedal (slightly), fluid should come gushing out of that line. That would help pinpoint where the problem may lay/lie/be.

 

[DeadStang]

Re: Newbie questions on wheel cylinder functionality

In preparation for some brake line work there, and while the car is still up on stands, I've already started spraying PB Blaster on the connection of that line over the rear axle housing. It looks pretty stuck together. I wouldn't try to remove lines until I've soaked it for several days, tho, or I may end up needing the tow truck to get it into the shop. As of now, I think it's still totally drivable and can get there under it's own power. I actually didn't notice any issues with the brakes driving the car a couple of weeks ago--I just thought it was a good time to flush the fluid since it's been several years. Another case of "While-Your-At-It-itis," I guess.

 

[crustycurmudgeon]

Re: Newbie questions on wheel cylinder functionality

In the world of Taurus SHO-dom, a common issue is swelling shut of the brake hose, with no outward indication of trouble. Perhaps the same issue with your Mustang?

Frank

 

[manley]

Re: Newbie questions on wheel cylinder functionality

In the world of Taurus SHO-dom, a common issue is swelling shut of the brake hose, with no outward indication of trouble. Perhaps the same issue with your Mustang?

Frank

There is only 1 rubber hose feeding both back brakes. I would say we can rule this out since the other side bleeds fine.

 

[AzPete]

Re: Newbie questions on wheel cylinder functionality

If the other rear brake works good, then you either have a line plugged from the "T" to the wheel or a bad wheel cylinder.

 

[jims6t6]

Re: Newbie questions on wheel cylinder functionality

If the other rear brake works good, then you either have a line plugged from the "T" to the wheel or a bad wheel cylinder.

Beat me too it Pete.

 

[gotstang]

Re: Newbie questions on wheel cylinder functionality

I wouldn't try to remove lines until I've soaked it for several days, tho, or I may end up needing the tow truck to get it into the shop.

If all else fails, you can always cut the line off short with a hacksaw and use a deepwell socket. Wrenches sometimes don't have the cajones to get them loose without futzing something up.

 

[DeadStang]

I removed the bleeder valve again and stuck a drill bit inside and wallowed it around and got no more fluid than previously. Next, I unhooked the hard line from the wheel cylinder and STILL got no fluid, which worried me. But I wrapped the hard line in a rag and pumped the pedal a couple of times (and the pedal felt like they do when you bleed brakes with 2 people) and fluid squirted out, so I knew the line wasn't clogged. I had a wheel cylinder from another project laying around, so I just finished installing that one and all is good! I didn't know that wheel cylinders could fail without leaking and being obvious. Thanks for the help! :bowdown

 

[AzPete]

May have failed by freezing in place with internal corrosion.