Brakes: new brake wheel-cylinders are weeping, never even driven the car. Need replacing?

[bsrosell]

For those of you who've patiently endured my leaking/weeping brakes as I learned to flare brake lines and fit a dual-cylinder M/C to my 57 Golden Hawk project, after four years, I've finally got leak free lines & M/C! (a 2nd gratis M/C from Jim Turner did the trick. Best guess, my "learning to flare" and repeated cranking on the fittings ruined the first M/C's nipples??)

SO, I was finally motivated to MOVE ON, and was going to button up the wheels and bearings tonight; pulled off the drums just to remeasure the spindle diameter, as I was debating peening or Loctite for inner bearings. Confirmed only 0.002" under so planning to let the spindles be.

HOWEVER, I noticed a 'drip' on the edge of one of the wheel-cylinder rubber boots. REALLY!!??
(For everyone else, my Hawk project is still just a chassis; the body still on a cart, so the only "brake action" these cylinders have seen is me manually pushing the brake pedal as I chased down my brake fittings & M/C connection weeps, and re-bled multiple times.. 2019-2023!).


Pulled off the rubber boots on all four cylinders, and all but one had some DOT5 sitting in them. ONE side of one cylinder completely dry....

I wiped them out really clean, then did some more pumping of the pedal (w/ drums on of course). Repeated this cycle three times (about 100 pedal pumps in between), and still have ‘wet’ pistons each time. 2nd photo and shop rag shows this “new fluid”. Not a heck of a lot, but seems there shouldn't be ANY?


In frustration, I gave up for the night to bounce it off you all.

Important note (may be the problem): I purchased the whole set of cylinders way back in 2011 with a bunch of parts I "knew I'd need ". I didn't actually assemble them to the car until 2017, and noticed there was some very slight corrosion starting inside the bores, and on the pistons. I easily cleaned this off with Scotchbrite (see before and after), and had all parts spick and span for re-assembly and mounting on the car (in 2017). Since then, as mentioned, only manual pumping of the brake pedal during these last four years of brake-misery.


Only three things I can think of to explain the presence of DOT5 outside the pistons WHILE rebuilding the car:

1) Scotchbrite isn’t the way to clean that slight corrosion, and the seals are leaking because of it?? And I need to replace all four cylinders. Again (if Scothbrite too aggressive, how DO you clean them then?)

2) Maybe there is enough residual DOT5 from assembly to still be showing up? (I lathered everything before putting it all together) that is still oozing off the pistons. (But, ONE piston is totally dry. How to explain that...).

3) these "new" cylinders have cheap seals and with slippery DOT5, just not a happy marriage?

I’m learning patience with this project.. but replacing unused new parts, with 2nd sets of new parts, is getting old. (have a torn 'brand-new' bearing seal in one wheel too. Sigh.)
Thoughts?
Thanks guys!
Barry

[StudeRich]

You are correct THIS is getting Old!
I don't mean for us to hear all this again, I mean: "For The CAR" ! I think this process is Just TOO slow with No usage.

It also occurred to me about the "Lube" DOT 5 seeping out of 3 Cylinders, but the 4th. one dry?? Did you forget to Lube it?

[bsrosell]

No, I dipped everything in DOT5 as I was putting it together on the bench. What I meant was, on one of the rear wheel-cylinders, one side dripped out just a little as I pulled the boot off; the other side appears dry. But that IS the 'upper' end of that cylinder. Only the one in the photo actually "dripped" outside of the boot, the others required removing the boots to see some fluid.
(yeah, slow process indeed. Now that I'm finally out of 3M I was hoping to get this show on the road. Not a great re-boot so far. (except fixed the M/C! )

[bsrosell]

(What happened to the edit button?.... )
I Forgot to add, with DOT5 and no corrosion, sitting shouldn't matter for this purpose? PLUS, the only thing that HAS gotten exercised IS these brakes, as every few months I've been out there to 'try try again' to fix the weeping brake fittings, flaring new lines, swapping M/Cs, etc. etc.. I don't see what 'time' would have to do with this particular problem??

[doofus]

Barry, you got me, i have the same problem with 2 of 5 drivers with Dot3 and new whl cyls. took 1 apart and found nothing wrong except cups felt like plastic instead of rubber! digging in parts box for NOS Raybestos kits. new kit from local flaps felt like plastic also! no corrosion just weeps. betting all will weep with boot pulled off! a Disc Brake conversion might be the only answer here! Luck Doofus

[Jeffry Cassel]

There is no way that cylinder is ever going to seal. I would replace them all. Swap meet stuff is always a pig in a poke. Like ebay.

[jg61hawk]

An old timer told me years ago to soak the internal rubber and maybe even the external rubber of new wheel cylinders in brake fluid for several hours or even overnight and then assemble. He said when he learned that trick he never had leak, but before that he often had leaks until the rubber swelled. Brake fluid does make rubber swell, eventually. Just a thought. I usually "exercise" my brakes often when the car isn't being driven on a regular basis.

[jg61hawk]

I can't edit...so I'll add...I wonder if the DOT 5 makes the rubber swell as did the old time DOT 3? If you look at the numbers, the 5 is different as it is silicone based.

[yeroldad]

A wheel cylinder hone and the rebuild kits are dirt cheap. If you wanna be real cheap, take a 1/4" steel rod or a bolt with the head cut off, then use a hacksaw and cut a 'split' down the rod, and wedge a piece of 1000 grit into the slot, and use your drill to hone the cyls. I've bought hones at local parts stores. The wheels cyls were new on my '53, but it had not been driven for a few years, so I spent the $30 and put in new cups and springs, I have a couple 3 hones. Simple. No need to spend a bunch of money on new complete wheel cyls. If it were me, I wouldn't bother with the wheels cyls or the master until you are ready to drive the car. They all go bad when sitting for who knows how long, without being used.

[mbstude]

Just IMO, but 6+ years is a very long time for a brake system to sit dormant with fluid in it.

Since this is a multi-year restoration project, I’d redo the brake system after the rest of the car is finished; just before driving it.

[christophe]

Just use Castrol red rubber grease or équivalent with all your hydraulic parts. Apply liberally under each rubber boot and your parts will last much much more longer without any least. I recently checked à car I rebuilt more than 25 years ago. Still no leaks!

[WCP]

I agree with Christophe, I use Permatex dielectric grease, particularly with Dot 5, to lube all wheel cylinder parts. No leaks over thousands of miles driven.

[christophe]

I almost forgot to mention that you must use high temp grease between all friction points. That is especially important for the contact points between the brake shoes, the backing plates, the cylinders and the adjusting mécanismes. The star wheel thread must be lubed as well.

[bsrosell]

There is no way that cylinder is ever going to seal. I would replace them all. Swap meet stuff is always a pig in a poke. Like ebay.

Jeff, I should have added that this cylinder kit was purchased from Phil Harris as part of a larger order when I initially started (and thought things would progress much faster!); he simply brought all of it, plus my supercharger rebuild, to the Springfield Intl Meet in 2011. So, US-made quality parts.

All,
thanks, good points to consider. Looks like probably rebuild of cylinders at least.

One other question: IF you think my problem is the caliper sat (w/ DOT5 in constant contact…) too long, wouldn’t it just be the “cup” of the seal around the piston that may have …..”dried out”? And if so, wouldn’t the seal refresh with use? (Like each time I manually have pumped the brakes).
NOT ARGUING, simply trying to understand; is it possible that with continued use the seals would “seal up” again.

. I’ve spent all afternoon reading posts (mostly Corvette club) regarding DOT5, and folklore vs facts. Many of their brake vendors send “not warranted with DOT5” in recent years, but WHY was subject of many posts. Best I could glean was that EPDM rubber is used for the seals, there is no issue.

Doofus; did you find Raybestos rebuild kits for your cylinders? One of the Corvette posts said they use EPDM (and they sell DOT5 brake fluid). I would think our vendors would know or be able to find out if EPDM is in their new rebuild kits (or complete cylinder or M/C kits). (Rich, do you know?? Or have additional info on DOT5 and effect on rubber seals?

My head was spinning after the Corvette posts, everything from “DOT5 formula has changed” to “seals are no longer compatible with DOT5”, very little documentation, except for a post w/ a Parker Hannafin tech bulletin that EPDM is recommended for use with DOT5.

I plan to call Jim Turner and ask if the new M/C he sent me has EPDM seals. It is made in China, vs the good USA made unit he initially sold me several years ago). One reason I kept trying and trying to make that ‘original’ US-made M/C stop weeping, honestly.

You guys are great. Thanks as always!

[bsrosell]

Just use Castrol red rubber grease or équivalent with all your hydraulic parts. Apply liberally under each rubber boot and your parts will last much much more longer without any least. I recently checked à car I rebuilt more than 25 years ago. Still no leaks!

Christophe,
1) do you mean apply the grease (or the dielectric grease I already have, per WCP) to the OUTSIDE of the rubber seals? You don’t want that or any other substance in contact with the side that will be immersed in DOT5, correct?? Could you clarify, “all your hydraulic parts”?…..where exactly are you applying the dielectric grease? What I did was dip each piece (seals, pistons, coat inside of each bore….) with DOT5 before assembling. Ditto with M/C.

2) re: high temp silicone brake lube, yep, religious about that on ANY brake job (though never thought of it for the star-wheel thread! Good idea!!)

Thanks!