Leaking wheel cylinder

[Rodney_Hamon]

I made the mistake of reversing the newly resleeved rear wheel cylinders on my ‘36 truck. R is the left drivers side and vice versus. I did this last summer and had no leaks. Then end of winter the driver rear started leaking. I pulled the drum off and checked for dirt and couldn’t see anything. I reinstalled and it was good until I came back from WI last week. I pulled the drum off again and noticed the reversed cylinder.  Is this causing the weeping?  Wrong side? Should I switch them to the proper side?  I didn’t have proper copper washers but I guess I can learn how to anneal them as they are thicker than what I have been able to find. I am a dumbkoff for the dyslexic install. Btw, Whitehorse re-resleeved the cylinders as they were restored in 1975.  The fronts from Napa and ok so far. 

[DJ194950]

?

 

What is the longer spring doing running from the rear shoe to the bottom for the same shoe? Should be between the front and rear shoes in the hole where you have the spring in the rear shoe.

 

Where is the front shoe spring that hold the shoe to the backing plate as is on the rear shoe. The smaller/shorter spring with the washers (2). ??

 

DJ

[Young Ed]

Putting them on opposite sides shouldn't cause a leak. But while you have it apart to resolve the leak you might as well swap them side to side

[wallytoo]

the leak wouldn't be caused by installing on the "wrong" side, so i wouldn't worry about that.  you'd probably never notice the difference in how the brakes function, either.  if the leak is from the rubber boots, you might need to inspect the cylinder bores for scoring.  if no scoring, might be able to get away with just replacing the boots and rubber cups, or even just the cups.

[Rodney_Hamon]

The spring and parts are on the ground and I left the main spring hanging. I was going to remove the front shoe to inspect the inside of the cylinder for any crud. I wasn’t going to remove the cylinder from the backing plate but I probably will now. Shoot. It’s a new rebuild with a second resleeving and 1936 is unique to that housing size fitting into the backing plate. I may have to send it back or call them. 

[Rodney_Hamon]

Ok. Question. Would driving it help to seat the cup against the boot and piston?  Or, would tapping on the brake pedal occasionally to keep pressure on the cylinder work. When I put it back together it seems to stay dry and then when I leave it alone and relaxed it seems to weep out the leading edge only. Step bores. The larger bore of the cylinder should be leading, right?  

[kencombs]

Just a long shot suggestion, but a missing or defective residual pressure valve in the master cylinder will cause a total loss of pressure over time.  That residual pressure keeps air out and also holds the cup lips firmly seated.  Also, some wheel cylinders have a steel cup and spreader spring to keep the cups lips firmly against the cylinder wall.  I'm not sure if that applies to '36 but, Either of those could contribute to a seep

Edited June 10, 2021 by kencombs

[Merle Coggins]

I had a wheel cylinder do this, but I haven't noticed it lately. When parked for extended periods the residual pressure would bleed down allowing the cup to relax and seep a little. Once there was pressure in the system again it would be fine. It has either corrected itself over time or I just haven't noticed it. 

 

Also, I believe the larger piston should go towards the rear shoe. 

[wallytoo]

8 hours ago, Merle Coggins said:

Also, I believe the larger piston should go towards the rear shoe. 

 

yes.  but, kind of like left-hand lug nuts/studs.  not needed, which is why the bores later were made the same for both sides.

[Rodney_Hamon]

Ok. I finally reversed the wheel cylinders to their proper location. Put everything back together and added fluid and bled and that pesky cylinder started weeping. When I initially got it back from restoration and installed it, it seeped so I sent it back in 2019 and White Post repolished the bore and put new seals in again and pressure tested it. After 4 hrs it had no leaks. Ok.   So...the other 3 are holding and this one is cursed. Upon suggestions I may leave it and just see if it adjusts.  Is there another place with fresh eyes that might be able to troubleshoot it?

[JBNeal]

is it weeping at the cup seals, bleeder screw, and / or inlet? 

[wagoneer]

7 hours ago, JBNeal said:

is it weeping at the cup seals, bleeder screw, and / or inlet? 

 

 

@Rodney_Hamon Why not get a "new" wheel cylinder from AB that also comes with a bleeder screw. Your beautiful truck is at the right stage to fix these problems before you go through more assembly. For $50, you can solve this problem reliably, and leave the original piece as a backup.

 

ps: I love the white cab. My truck cab was also white at some point, and I like how the light reflects off the inside and show so brightly even at night.

Edited June 18, 2021 by wagoneer

[Rodney_Hamon]

It is leaking from the cup. What is AB ?  Andy B ?  The backing plate only accepts the ‘36 size unfortunately on the rears. My P-23 was so easy to redo brakes wise. Sometimes I think I’m going to switch backing plates from my parts car and put onto the dodge. I also considered swapping the ‘38 Plymouth rear end under the dodge as it’s backin plates take average size wheel cylinders. Alas, it’s 2 inches wider.  

[kencombs]

If it were mine I'd disassemble the cylinder, examine and  measure the bore, and be sure that the cup expanders were in place.  Then order a set of cups of the correct size and expander parts if needed.  Lots cheaper than even paying shipping both ways for the original vendor to attempt to correct.

 

Dorman has cup and kits available for most every bore.  Probably won't have it listed by application, but easy enough to determine size and buy the 'generic' parts.

[JBNeal]

What does White Post say about this recent issue? It sounds to me like the issue has to do as pointed out with those cup expanders, as the seal is working under pressure but not so much when pressure drops.

[ggdad1951]

I fought a weeping cylinder for about a month....replaced it and the problem went away....just my fraction of a penny's thought.

[Rodney_Hamon]

Wagoneer- Thanks for the white color comment and the others for their advice. I admit when my truck was first painted in ‘75 it was gorgeous. Now I wish I had put it to original blue but I was a 20 yr old. Now I just saw a gorgeous gray on a fancy Porsche that sure would look good. Ha. Now I’m a 66 yr old. Ha  I started the engine with the new battery cables setup. Ground to the head. I have a strap from the cab to the chassis now.   And I purchased 2 rear wheel cylinders that just came available eBay. Ouch was the price but I want to resolve the brakes and will whittle on the weeper later. 

[Rodney_Hamon]

Success with replacing the leaking wheel cylinder that came from moparpro.com.   So worth the $150 for the pair. If the other weeps any time soon I have a backup. I see the site sells a drum puller. Worth it. I don’t know how anyone could do brake jobs on mopars w/o one. Got first clear coat on the cab back and been cleaning the rear end and the springs etc.  Got the old tires removed from the rims so I can start the cleaning process. Tire shop said just prep really good and spray with a good industrial