Rear Brake Cylinder Question

[Vorticity]

So I did something stupid after replacing my brake booster and master cylinder.  I forgot that I had removed one of the drums and got in the car and pumped the brakes.  The absence of the drum allowed the piston in the wheel cylinder to overextend and it pushed the its rubber boot loose a bit, causing a squirt of fluid on the garage floor.  I was able to push the boot back where it goes and reposition the clip to hold it, but the piston won't go back inside the cylinder far enough to let the pads retract enough to get the drum back on.  I cracked the bleeder to release pressure, hoping this would help, but no joy.  

Am I going to have to pull off the wheel cylinder, take it apart and put it back together?  I'm hoping for an easy fix.  Got any tips?

Thanks,

Matt

[AK260]

Firstly, rest assured that we’ve all done something like that.

When I did it, I just popped it all back in again without issue. Are you sure something isn’t in the way in there?

[Vorticity]

8 minutes ago, AK260 said:

Firstly, rest assured that we’ve all done something like that.

When I did it, I just popped it all back in again without issue. Are you sure something isn’t in the way in there?

I don't think there's anything.  Here's a picture.  

[Zed Head]

Pop the rubber boot off so that you can see the piston.  It might just be cocked.  The boot is just a dust seal, the cylinder would actually work without it.  But it's obstructing your view for now.  Open the bleed valve and manipulate the piston until it slides in like it should.

[Vorticity]

27 minutes ago, Zed Head said:

Pop the rubber boot off so that you can see the piston.  It might just be cocked.  The boot is just a dust seal, the cylinder would actually work without it.  But it's obstructing your view for now.  Open the bleed valve and manipulate the piston until it slides in like it should.

 

Do you think I need to take the pads off to do this?  Seems like it.  I don't have one of those retainer removal tools.  

[Zed Head]

"Shoes".  The retainer will pop off with a thin screwdriver or a pick or needle nose pliers, I think. 

It kind of depends on what you can see when you peel the boot back.  Take it a step at a time and see how far you get.  You might be able to pull the shoe back enough to reposition the piston.  Good luck.

[siteunseen]

You can use needle nosed pliers to push in and turn the retaining pins. Then pull both shoes towards you and they'll collapse together and the springs will fall off.

 

[Vorticity]

I managed to pry the "shoe" far enough off the piston to be able to fiddle with the piston and get it to retract.  Thanks guys.  Next issue is that I cannot get the brakes bled properly.  Squishy peddle that gets firm when you pump it.  I bled in what I think is the proper order.  Bench bleed the new master, then bleed left rear, right rear, right front, left front.  I'm tired. I'll tackle it another day.  

[Vorticity]

BTW, what an odd wheel cylinder.  Only one side moves.  

[jfa.series1]

3 minutes ago, Vorticity said:

BTW, what an odd wheel cylinder.  Only one side moves.  

These cylinders "float" or slide when the piston expands, its good to apply some grease to that area when installing.

[AK260]

I managed to pry the "shoe" far enough off the piston to be able to fiddle with the piston and get it to retract.  Thanks guys.  Next issue is that I cannot get the brakes bled properly.  Squishy peddle that gets firm when you pump it.  I bled in what I think is the proper order.  Bench bleed the new master, then bleed left rear, right rear, right front, left front.  I'm tired. I'll tackle it another day.  

Well done for sorting out the cylinder. [emoji106] No matter how much we know, we are all learning every time someone else has an issue!

I find using a clear tube and opening the bleeder very slightly works a treat. In my experience, I have found that sometimes even though you haven’t raised the pedal yet, it sucks air in through the side of the bleed nipple. So I undo it a little and tighten again while it’s still squirting out.

My method:
3 pumps of the pedal by your helper, keep it down, undo nipple slightly and watch the air come out in the clear tube, close the nipple quickly before it stops flowing.

Finally, I had air coming back into the system at the front right since I re-made the brake lines. Could not figure it out until I found a leak on the rear left!!! Strange how the air works it’s way around the system!

[Zed Head]

18 hours ago, Vorticity said:

 Next issue is that I cannot get the brakes bled properly.  Squishy peddle that gets firm when you pump it.  I bled in what I think is the proper order.  Bench bleed the new master, then bleed left rear, right rear, right front, left front.  I'm tired. I'll tackle it another day.  

Can you tell which corner has the air in it?  See bubbles come out of the tube?  Hate to bring i up but you might have damaged the seal on that piston and it's sucking air.  Just a big Maybe to check for.  Big MAYBE, don't know, hope it's not, but it could be.

Beside that you probably drew a lot of air in to that cylinder when the piston was unseated. Spend a lot of extra time purging that one.  Tap on the lines, fittings, and cylinder to break any small bubbles free.

The fronts are where a lot of air can hang out.  Did you do any work up there?  Bleed screws up...

Brakes are the biggest pain on these cars, I think.  Since you had the master cylinder off there could be air working its way through from there, through the NP valve, and the pressure imbalance warning switch, and the various junctions.  Just a lot of little spots for a bubble to hang up.  I put speed bleeders on the backs so that I could push a lot of fluid through quickly.  Many people like the speed bleeders.  They help.