New wheel cylinder leaking

[Carguy4sp]

I just finished my all drum brake rebuild on my 72 Q code 4 sp.

I tried bleeding the brakes and I have a healthy leak on my left rear inside the drum.

I have not pulled it apart yet but I seem to remember reading about if you did not adjust the brake shoes out after install it will make wheel cylinder leak.

Could that be the case?

Yes yes all wheel cylinders are new from auto zone (low quality my opinion).

All hardware is new.

I will pull it apart tomorrow and look for leak. Just wanted to see if anyone has had this same type of issue ?

Thanks

Rodney from SW Florida

 

[rocket366]

New wheel cylinder should not leak!

Brake adjustment is not a factor.

A rubber cup in the wheel cylinder could be installed backwards?

Paul

 

[piper62j]

It is possible that one of the small extension rods that fit between the wheel cylinder and the brake shoe is not making contact with the shoe. As the piston moved outward during the bleeding process, it overextended its' reach and the cup inside the cylinder has dislodged itself causing the leak..

Like Paul said, it could also be an improperly installed cup.

 

[Carguy4sp]

Ok today I removed the wheel and brake drum and had my wife slowly apply brake pressure.

It took some time but I was able to find the leak. It is leaking at the hard line connection to the wheel cylinder. I gave it little extra snug tightening but it still leaks. It could be possible that the wheel cylinder has a deep cavity and the line is a shallow cavity line.

The car had brake problems when I bought it so maybe the hard line is bad.

Any troubleshooting tips?

 

[Carolina_Mountain_Mustangs]

I would take the wheel cylinder back off and take a close look at the seat inside that the line seals on. Look for damage from trash and you can usually see if the line is seating. Also always clean the ends of the brake lines with wire brush / steel wool and pump a little fluid out to clean out inside. Make sure that the cylinder has inch threads not metric also. If you have a flaring tool clamp up the line and squeeze the angle on the line again to maybe true it up.

When putting new cylinders on I like to put just a little anti seize on the threads not on the flare just the threads to keep them from locking on so tight. I also put a small amount on the bleeder valves to prevent sticking there also just threads not seat. Use a pipe cleaner and use very little.

Always use line wrenches to do the work so you can get a good grip on the hex.

Also pump enough fluid through the lines to get new fresh fluid in all the lines and cylinders. Brake fluid absorbs water and yes you can check it with kit from parts house but fluid is cheap so just pump in through and change it.

I think Ford went from inch threads to metric in wheel cylinders somewhere in the 80's.

 

[Carguy4sp]

Thanks everyone.

I think it is china poor workmanship issue.

I ordered a new one on line premium edition.

I will also do as everyone has suggested about inspecting and cleanliness.

I have also read about locktite 545 thread sealant and my try that as a last resort, do not want to change out the hard line.

Thanks

Rodney from SW Florida

 

[rocket366]

So it's not the threads of the flare nut that make a seal.

It is the flare on the end of the brake line that seals on the brass *** inside the

wheel cylinder that makes a seal.

An imperfection on the flare like a split or a deformed brass *** will be the issue.

No amount of thread sealer on the flare nut will resolve this!

Good Luck

Keep us posted

Paul

 

[Danno]

So it's not the threads of the flare nut that make a seal.

It is the flare on the end of the brake line that seals on the brass *** inside the

wheel cylinder that makes a seal.

An imperfection on the flare like a split or a deformed brass *** will be the issue.

No amount of thread sealer on the flare nut will resolve this!

Good Luck

Keep us posted

Paul

Is there a copper crush washer missing?

 

[rocket366]

There is no crush washer on wheel cylinders only on calipers.

The connection will need to be fairly tight and you should use a flare-nut wrench.

Paul