I replaced one of the two wheel cylinders in my '79 Catalina yesterday, and I don't like the way the factory line threaded into the new cylinder so I thought I'd get more "professional" opinions. Haha. I've never done one of these. I attached an image. The threading doesn't go all the way to the base of the unit like the original one did. It took some wrestling and angling to get it to catch in the threads in the new one. It's not cross-threaded, as I turned it a good 2-3 turns inside the assembly before it started getting tougher to turn. The original wheel cylinder fit it like a glove. I discovered it was actually made a few miles down the road in my hometown, Dayton, Ohio, at Moraine DELCO. Sadly, it's not there anymore. Old US vs modern Chinese quality.
I personally don't think this is ok, because pumping the brakes made fluid appear on the axle, not far from the wheel. I couldn't tell where it was coming from, but that line didn't leak before the cylinder came off and I put this on.
If this is not a problem, I also want to make sure it's ok that the wheel cylinder's pistons moved a good bit inwards from spring forces while I was reassembling the drum. Will this pop back out when fluid pressure hits it, or did I damage the cylinder?
If I were going to the trouble to replace wheel cylinders, I would do the complete brake job anyway, which requires complete disassembly. By complete, I mean new shoes, a new spring kit, cylinders, cleaning and lubing the star wheel adjusters, and lubing shoe contact points on the backing plate and other hardware.
me too
Me three.
I'm definitely not a professional but have been dealing with drum brakes for something like 50 years now.
Since brake fluid is leaking at the axle either the line is not threaded in there properly (hopefully it really is not cross-threaded) or the line itself has started to leak due to age, corrosion, and being disturbed. It's possible the China-made replacement cylinder has fewer threads. The flare on the line has to fit right up against the matching surface in the cylinder and the flare nut holds it in place. Don't over-tighten it.
The pistons being pushed in due to spring pressure will not harm anything. They will move outward with hydraulic pressure, though as I've mentioned before you need to be careful about that when the drum is off or the pistions can pop out.
Did the brake lining set come with primary and secondary shoes? If so, the primary shoe will have a shorter length of friction material and it goes on the front. It looks to me like you have that setup but can't tell which direction is the front of the car from your photo.
The front of the car is to the left. I took a couple photographs before I tore the thing apart to keep as reference, they didn't end up being all that useful, as I didn't get great angles, but I was able to jigsaw puzzle it back together based on my knowledge of how they work, the photos, and the experience I gained from tearing apart my truck's drums. I have 1 year before I have a mechanical engineering degree, so I'm pretty good at visualizing things like this. Haha. The car is sitting on an old, compacted gravel driveway. I placed two half inch sheets of plywood between the stand and ground to spread the load on the gravel. It seemed to hold the weight fine for 4 hours. I don't trust the setup enough to take both wheels off at once, or I could've used the other side as a guide.
OK, you have the primary shoe facing the right way then. You'll need to closely check your brake line and fitting where it goes into the cylinder. As I said, make sure the flare is seated in the cylinder. Also check for any burrs or other defects in the cylinder since that would cause a leak. (Defects in a Chinese-made auto part? Unthinkable!)
Is there a trick to be able to pull that cylinder off without tearing apart the drum again? I watched a video earlier with a guy who was able to do it, but his adjuster was above the center of the wheel, not below it, like mine. I'd make my life a lot easier if that's possible with this style drum, lol.
Afraid not, I don't see how it could be done with the shoes (actually the plungers attached to the shoes) being pulled into the cylinder by the springs.
There is no trick to pulling off the wheel cylinder. It all has to come out.
I saw a video a bit ago, a guy You removed the 2 retainer springs and tensioner for the adjuster at the top, and he removed the adjuster gear from the bottom of the shoes. They will pivot outwards on the capped pins, due to the lower spring pulling them together. For designs with the adjuster in the middle, you can remove top springs and open it enough to pop out the cylinder. Clever thinking. The retainer pin springs are my least favorite part of drum assembly.
OK, I can see where that could work, learn something new every day. I'd probably still take it all apart though so everything is completely out of the way.