Whaaaa, whaaa, whaaa, Leaky wheel cylinder whiners!

Now that I have everyones attention, lets go over this issue with new wheel cylinders leaking. I've had this issue with customers for years and found that in the large majority of issues it is not with the wheel cylinder but in the handling of the item by the customer or packager. In fact I had this discussion with another vender yesterday about a return cylinder claimed being defective and upon inspection revealed no issue. Since most of the issues usually center around wheel cylinders that are stepped bore sizes lets start here so that you can understand what the majority of the issues are and why you are unreasonably whining..

First the biggest problem is the tendency to play with the wheel cylinders pistons by squeezing on the piston pucks when you remove the cylinder from the package with your fingers. Yes its neat to feel the pistons move but you could be doing more harm than good. This action creates the major source of leaks in new wheel cylinders.

When the wheel cylinders are compressed with no fluid inside the seal cups have a tendency to disslodge or be displaced from their bore seat especially the smaller cup into the larger bore opening. Once the sealing cup has been displaced it allows fluid to flow around the seal cup and escape thru the clearance between the piston and the cylinder wall. The brake actually works to a degree but the cylinder leaks when the excess fluid finally fills the exterior moisture shield cup. What is the cure?

The cure is simple, Dont play with the cylinders when you open the box. But as a precaution and since most of you are somewhat handy with tools and understand mechanical things here are some pointers.

When you are replacing wheel cylinders one of the first things you should do after opening the box is to pop the cylinder moisture covers, pop the piston pucks and check the seal cup seats remembering or drawing a diagram of how they were dissassembled..

While you have the cylinder opened up lube the seals and side walls with a very light coat of brake fluid and reassemble the parts in the order they were installed. Hint, as you are transitioning from one bore side to the opposite side fill the cavity with a small amount of brake fluid so there will be no air void between the bores. This also speeds up the bleeding process by removing the majority of trapped air. Finish reassembly and clean off all excess or spilled fluid. If you keep the bleeder valve closed no fluid will run out the nippple port and you then can assemble the line to the cylinder and install the shoes. After installing the shoes and the drums you can now go thru the normal brake bleeding process.

If you have experienced a leak from a newly installed wheel cyinder first dont whine to the vendor about the poor quaility country of origin crap. Remove the offending part clean and dissassemble and inspect the part and reassemble as instructed. If there is a defect found in the parts due to damage then you can whine, if the part reassembles with no issue pat your self on the back for doing a good trouble shooting.

Note installing wheel cylinders dry can create the same issue of dislodging piston seal cups when the brake retractor spring is clipped into the opposing shoe the tension used to clip the spring to the opposing shoe can force the shoe pin to compress the wheel cylinder piston far enough into the empty bore to also dislodge the seal cup and produce a leak. So its a good idea to fill the wheel cylinder before installing anyway.

I hope this clarifies to a degree one of the wheel cylinder leak issues that some have been experiencing.

 

Thanks, and yes I admit I pushed the pucks together before....
they are super easy to take apart and clean, and yes I have had to do this before.

 

Great advice Dick,,I learned my lesson long ago in my teens from a curmudgeon mechanic not to squeeze a wheel cylinder and being a teenager I wasn't going to listen to that old bastard.

He proceeded to instruct me on how to do the job and when it came time to bleed the brakes,,I discovered much to my dismay that the cylinder I was playing with leaked like a sieve!

From that day forward I considered myself fortunate to have had that old mechanic to guide me in my endeavors. HRP

 

Thank you for such great advice!

 

Thanks, Dick.

Can I call you Richard?

 

Guilty.
Thanks for the heads up

 

Thanks.

 

Good lookin' out!

 

Dick,
Any comments or recomendations about using brake assy. lube instead of brake fluid for cylinders/systems that won't be flushed out for a while, months or even years. Parts sitting around with brake fluid in them will collect moisture with the resultant corrosion, then you are back where you started from.
Thanks, Deloc

 

Things have sure changed through the years as they always tend to do. I attended a well known Tech College for automotive repair back in 1972. They taught us things like Dick was referring to. Troubleshooting and rebuilding things like wheel cylinders, starters, alternators, transmissions, power steering pumps, a/c compressors etc. I wonder what is taught now as most dealerships and repair facilities just replace parts. thanks Dick for the reminder of lessons learned a long time ago.

 

Thanks for that bit of advice Dick. From years of repairing brakes that the car owner had inflicted problems into when they attempted to do their own brake jobs to "save a few bucks" I can see that this can be an ongoing issue.

Good advice on popping the dust caps off and checking to make sure that everything is in place where it should be after checking the diagram in the book.

 

I've been yelled at enough to know not to do this..... Thanks for the great advice!

 

Thank you, Mr. Spadaro. I learned something today.

 

Sounds similar to advice not to spin new bearings before they are lubricated.

 

times two

 

I have noticed however that most of new wheel cylinders are not honed to a smooth finish rather just machined cast iron and roughly done at that(so thats me whining about the cheap china made crap). hitting them quickly with a hone and brake fluid seems to keep the cars that do a lot of sitting from leaking over time.

 

Good info-thanks.

 

Guilty again. Thanks

 

If the manufacturers would just put those light springs and cup expanders in there like they used to, we wouldn't have this problem.

 

Dick, ever seen any where the feed hole is drilled through partly up the bore like this?



I have 6 like this sitting unused.

I'd appreciate your opinion.

Mart.

 

Hi Matt I dont know where you got those but nothing makes sense. Easy rational is that it must be photoshop. Now back to the question, the fill port in a wheel cylinder is drilled at an angle to intersect the sleeve bore at the diameter measurement point. If the drill was over bored it would strike the opposite wall 180* from the inlet hole. Your pictures show a hole drilled in the body at a point less than 90* from the inlet hole so that would mean (and because you are from the UK) they used a James Bond bendable drill. Even if you said that the bleeder port was over drilled the hole for that port would be directly adjacent then fill port on a chord distance to the opposite side, nowhere near the seal area. Stick a tooth pik thru the inlet hole and thru the bleeder port and determine if they intersect or where they interact with the hole in the bore. So right now you have still have 6 mysteries. Show a complete shot of the cylinders and a shot of the inlet boss.

 

What I think Mart is trying to show is that the inlet hole on his defective cylinders are drilled well down the bore where the cup rides, instead close to to step like the bleeder holes are.

 

Meester Spadaro, I just had three new chinese wheel cylinders that would not stop leaking, no matter what I tried. Please tell me how you test these when you get them back. It was the bleeder valves that were leaking. Right rear on my avatar

 

Dick, 4 of the cylinders came from Macs, I bought 2 kits with master cylinder, 4 wheel cylinders and hoses - you know the ones. The front cylinders were ok, one of the rears leaked as soon as I put fluid in the system. I bought 2 more from a UK supplier but although they come in Ford approved parts boxes, are obviously from the same manufacturer and just the same.

I emailed Macs but after telling them all they needed to know the communication stopped.

Here's an old made in USA cylinder - note the position of the feed and bleed ports.



Here's the same image as above showing the mis-drilled feed hole.



Here's a shot showing the angle of the drilling in the Old made in USA cylinder.



And the recently bought one.



You can clearly see the error in the angle the hole is drilled at.

And even when you put them side by side you can see the difference.



I bought these cylinders about 12 months ago and I would imagine they are being sold very widely by a lot of suppliers.

Nothing would please me more than to know these dangerous wheel cylinders are no longer being sold. But without being able to adequately explain to the seller what is wrong with them, how can they approach the manufacturer to start making them correctly?

As a person in that line of business I would appreciate your input. It would be nice to know there is a supplier that can sell parts that function as they should.

Mart (with an r).

 

Good catch Mart.

 

Hi Mart, thanks for the pictures. While you think nothing may be transpiring about this a few phone call have been made regarding your issue. It seems to be difficult to determine the importer or the repackager of such items since there are no MFG marks on the product. Your new pictures are much more explicit than the original shot and from them it seems like this unit has a different design and angle to the inlet port casting than an original wheel cylinder. Recent source has been Asia but wheel cylinders also come from Italy and other countries.

From what I can see from your shots the feed hole in the cylinder it too high up in the barrel because the inlet port is drilled at the wrong angle. With the shoes fully retracted this opens the cup lip on or below the port and when pressure is applied the seal doesnot function correctly. In some cases where the customer has over size turned drums and the shoes are in the expanded stage the cylinders do not retract enough to expose the port. But if you have new drums or oversize shoes which position the piston further in the bore the port is exposed and the cylinder leaks.

I dont know why MAC's has shelved your inquiry but I do know they have an excelent data base and would be able to somewhat cross your customer number and purchase thru their system. Thus to check back on supply purchase dates that would close to determine the supplier of the part. If you have saved any of the boxes please let me know what the supplier # is, that is the bold print 6 digit number on the right.

This is the weekend so let me make some calls next week and I'll see if get some more information. DS

 

I took mine apart for inspection before using and glad I did, there were metal shavings in each one......now crap I have to do it again and check for incorrectly drilled hole?

 

Very informative.. Thanks...

 

Thanks Dick.

Mart.

 

I have a question.

My 64 has metal "links" on each side if the cylinder. The new cylinders I bought didnt have the links included, I sourced some from Napa after a few curious looks from the counter guy insisting their were suppose to be links.

Are you suppose to grease the links upon installation? so the rubber cups slide easily over them?