Wheel Cylinder Mystery

[55 Fargo]

Hey all, did post some of this in the MC thread, but may not have been viewed by many.

Recently, I needed to install a new wheel cyl on the rear of my 55 Fargo, these are modern brakes, 10 inch 1988 Dodge. After installing the wheel cyl, new brake line to Tee block, proceeded to bleed brakes.

At first my MC was going to the floor no pedal, then it cam back up, and I was able to bleed brakes.

I then did notice, the new wheel cyl was weeping some fluid, removed the drum, cleaned it up, and reinstalled, same thing but less after a drive.

I then pulled shoes, cleaned mess, reinstalled, making sure pins were in wheel cyls correctly, and brake shoes fastened back into place. I adjusted brakes, and so far no more leaking.

I have no idea what went on here, if 1 of the rubbers were not sealing or something at first.

But I do now have an external leak going on from the MC, will deal with that, but it was not leaking to my awareness, until I did this recent brake work.

Anybody ever experience something similar?

[HanksB3B]

C38Spitfire6,

 

Just a guess but lets say the system as a whole withstands 100 psi pressure.  The leaky slave cylinder was the path of least resistance and so that's where the "system" leaked from.  Now you've plugged the hole so to speak and the master cylinder has become the weak point. The rubber boot is to prevent the elements from causing rust and has nothing to do with containing fluid leaks.  The entire system including a new master, new slave cylinders and new brake lines can be done for about $400-$450. Probably the one part of the truck I wouldn't skimp on. It used to be I'd fix one slave cylinder then next couple of weeks another, then two months from then another. I know it might seem expensive but with these trucks there's nothing worse than limping a truck off a hill with bad brakes.

 

Hank 

[Plymouthy Adams]

I agree..brakes are critcal..number safety aspect of most moving vehicles..but with the number of out of box failures of the items currently on the market, the mix match of piston and pin designs getting all co-mingled..it is a headache from the get go....if you are not rebuilding your own units or shipping them off for a stainless or bronze lining..you pretty much at the mercy of the suppliers....now to address the cost involved in money out the pocket combined with the aggrivation and the downtime...one cannot but see the the reasoning of upgrading to modern stuff..but I ALSO SEE that folks want the originality of the components thus they endure..not sure there is an easy fast snaser here..no sure of the casting quality of the offshore parts..do not rule out the fact that holding onto your old parts, celaning the piston adn pin is a quick answer for mix match..,the pistons are not a sealing items so they can be transferred if not heavily damaged in some manner

[55 Fargo]

Thanx Guys, I have spare wheel cyls, and even another MC, but of course need rebuilding and possibly sleeving. I think I will open up the spare MC, and see what I got, sleeve if needed, the same ofr the front wheel cyls, that are not leaking whatsoever, I may not distrub those, all is well.

The old wheel cyl did not look that bad, but there was some debris in it, perhaps the cup was leaking for that reason.

I will report back my findings, when I know.

On my 47 I got lucky, all OEM MC wheel cyls,honed and new kits 7 years ago, new lines hoses and shoes, DOT 5 fluid, all is well, without needing any re-sleeving

[TodFitch]

C38Spitfire6,

 

Just a guess but lets say the system as a whole withstands 100 psi pressure.  .  .

Looking at the brake pedal on my '33, there is at least a 5 to 1 leverage (pedal goes down about 5 inches for each inch of master cylinder piston travel). I can press 200 lbs with one leg. I assume in an emergency stop the excitement could lead me to do more. So were are looking at about 1000 lbs on the master cylinder piston. My master is 1 1/8" in diameter or almost exactly 1 sq. inch. So we have 1000 psi on a quick and dirty calculation. For a reasonable safety factor I'd guess that the brake system should be able to hold at least 1500 psi and maybe 2000 psi.

 

That is a bit more the 100 psi.

[55 Fargo]

Looking at the brake pedal on my '33, there is at least a 5 to 1 leverage (pedal goes down about 5 inches for each inch of master cylinder piston travel). I can press 200 lbs with one leg. I assume in an emergency stop the excitement could lead me to do more. So were are looking at about 1000 lbs on the master cylinder piston. My master is 1 1/8" in diameter or almost exactly 1 sq. inch. So we have 1000 psi on a quick and dirty calculation. For a reasonable safety factor I'd guess that the brake system should be able to hold at least 1500 psi and maybe 2000 psi.

 

That is a bit more the 100 psi.

Yes Tod, would be a lot more than 100psi in the brake sytem hydraulic pressure. I think Hank was making reference to the weakest link employing a number.

[Plymouthy Adams]

Being national certified in brakes and knowing the pressure are much higher also, I read it the same way Fred...100 to 0, 1000 to 0 or 2000-0 is still representing a high/low in a sealed system

Edited March 3, 2013 by Plymouthy Adams

[48Dodger]

1988 system? Then you you should have a vacum booster, bringing your potential to 2200 psi with assit. Are all your brake components "match" in terms of modern upgrades?

 

48D   

[55 Fargo]

1988 system? Then you you should have a vacum booster, bringing your potential to 2200 psi with assit. Are all your brake components "match" in terms of modern upgrades?

 

48D   

This would help the leak situation, a booster....LOL

here is the system, stock MC 1 1/4 inch bore, stock front wheel cyls 1 1/8 bores, rear diff 1988 Mopar 8 1/4 with 15/16 bore wheel cyls, with self energizing bendix type brakes.

I do not see the intent of your post. Ideally I could have a front disc conversion, a modern dual MC, but a booster, my leg is the dang booster.......LOL

[48Dodger]

I didn't read the MC thread you mentioned.....and you only refered to your MC as "My MC" here......so if you had the 88 brake/booster, it would increase your pressure to 2200, to much pressure in my opinion for an old/new blend. But I'm guessing you dont. We all understand leaks, but you said it developed a leak after you fixed the rear cylinder. If your pedal went to the floor....my thought is it was sucking air in and you were compressing said air. You bled the brakes, the fluid now top off, it helped expand the seals to seal it up. No more air. pressure increased....new leak. I bet if you fix your MC, all will be fine.

 

48D 

[HanksB3B]

Yes Tod, would be a lot more than 100psi in the brake sytem hydraulic pressure. I think Hank was making reference to the weakest link employing a number.

 

Correct, that was my intent.

 

Hank 

[55 Fargo]

I didn't read the MC thread you mentioned.....and you only refered to your MC as "My MC" here......so if you had the 88 brake/booster, it would increase your pressure to 2200, to much pressure in my opinion for an old/new blend. But I'm guessing you dont. We all understand leaks, but you said it developed a leak after you fixed the rear cylinder. If your pedal went to the floor....my thought is it was sucking air in and you were compressing said air. You bled the brakes, the fluid now top off, it helped expand the seals to seal it up. No more air. pressure increased....new leak. I bet if you fix your MC, all will be fine.

 

48D 

I am hoping that will cure my problems for now.....LOL

All else is fine, except the leak at back of MC, which You and I both know is fluid slipping past the seal.

I will have a look at my spare, and either rebuild,re-sleeve or replace....thanx

[55 Fargo]

Pulled MC from 1 ton truck frame, it was not seized, reservoir quite clean. The piston had some crud, the bore still has cross hatching pattern on it, some rust was going on though.

I do not think this would be a hone and kit candidate, but more likely will need re-sleeving.

[HanksB3B]

C38Spitfire6,

 

Just the other day I replied to a MC/Sleeving post where someone was asking $350 to re-sleeve a MC.  I suggested

http://www.vintagepowerwagons.com/  They listed a new MC for $149.00.  

 

Hank 

Edited March 5, 2013 by HanksB3B

[55 Fargo]

C38Spitfire6,

 

Just the other day I replied to a MC/Sleeving post where someone was asking $350 to re-sleeve a MC.  I suggested

http://www.vintagepowerwagons.com/  They listed a new MC for $149.00.  

 

Hank 

Hank, would rather send my MC to have it sleeved in the US, than buy those re-pops.,sorry.

This MC is in good shape, once re-sleeved for $100.00 I will bead blast the MC and install the kit myself. This will be much better than any foreign made repop................BTW you can buy and MC, from Rock Auto for less than $100, probably the same repop as VPW

Edited March 5, 2013 by C38Spitfire6

[TodFitch]

Hank, would rather send my MC to have it sleeved in the US, than buy those re-pops.,sorry.

This MC is in good shape, once re-sleeved for $100.00 I will bead blast the MC and install the kit myself. This will be much better than any foreign made repop................BTW you can buy and MC, from Rock Auto for less than $100, probably the same repop as VPW

Not sure who you are planning to have re-sleeve your cylinder but... my master and wheel cylinders came back from Joe at Sierra Specialties looking wonderful inside and out. I don't know how he cleans them up, but bead blasting was not neccessary.

[HanksB3B]

TodFitch,

 

Are you sure that VPW master cylinders are "re-pops"? How much did you spend to have your master cylinder re-sleeved? I bead blasted my original old ones and they came out like brand new.  I need to find someone to re-hone or sleeve them. How much does he get for the slave cylinders?

 

Thanks,

 

Hank   

Edited March 5, 2013 by HanksB3B

[TodFitch]

TodFitch,

 

Are you sure that VPW master cylinders are "re-pops"? How much did you spend to have your master cylinder re-sleeved? I bead blasted my original old ones and they came out like brand new.  I need to find someone to re-hone or sleeve them. How much does he get for the slave cylinders?

 

Thanks,

 

Hank   

Don't know a thing about VPW master cylinders. The one photo I looked at shows a cylinder similar to the one currently available through NAPA for less. And those both match the one I bought from a Mopar specialty supplier 15 or more years ago before I figured out that I could have gotten it cheaper. I don't know where that master cylinder was manufactured but it went out this year and I put in the original master cylinder that I had Sierra Specialties resleeve a few years ago. (The original for my '33 looks a bit different from the VPW one and I wanted to return to a stock look and the MC is visible on my car with the hood open so I had it resleeved and was waiting for a "round tuit" to install it.)

 

I don't recall how much I spent to resleeve. I try not to remember how much I spend on the car. But I guess I could look it up in my records. He posts his prices on his web site though. http://www.brakecylinder.com/prices2011.htm

 

Hmmm. That page now says "We have retired and are no longer accepting work. Information on this website is presented for historical and educational purposes only." So I guess I shouldn't recommend him any more.

[48Dodger]

"I try not to remember how much I spend on the car."

                                                                                       Todfitch

 

 

 

Amen brother  (the look on my face when i think I need to do the math..lol)

[55 Fargo]

TodFitch,

 

Are you sure that VPW master cylinders are "re-pops"? How much did you spend to have your master cylinder re-sleeved? I bead blasted my original old ones and they came out like brand new.  I need to find someone to re-hone or sleeve them. How much does he get for the slave cylinders?

 

Thanks,

 

Hank   

Hi Hank, and BTW, I do appreciate your's and others input,experience and advice.

I only figure these are new, and most likely re-pops, made ina foreign country, but I could be wrong.

They look exactly like the Oreiily, Rock Auto, Roberts MCs, with a top plate that bolts down as well as having a filler cap.

Rock Auto's MC is by far the least expensive, but who knows who is making these new MCs and wheel cyls.I am willing to bet, China, or some other foreign country.

Today I am very tired, lots of snow removal, heavy snow last night, just hope this is the last, but who knows up here. Then to top it off Older Boy buys 10 yo Boy a , 1988 5 litre Mustangbody, no interior, engine, seats, or glass, and now I am supposed to do something with this.

That leaky brand new wheel cyl, leaked today, , it was dry, moved truck today, and wet spot appeared, what a PITA.

I am going to tear down the entire hydraulic portion of these brakes, why the heck would a brand new chinese wheel cyl leak.....LOL

Edited March 6, 2013 by C38Spitfire6

[55 Fargo]

Don't know a thing about VPW master cylinders. The one photo I looked at shows a cylinder similar to the one currently available through NAPA for less. And those both match the one I bought from a Mopar specialty supplier 15 or more years ago before I figured out that I could have gotten it cheaper. I don't know where that master cylinder was manufactured but it went out this year and I put in the original master cylinder that I had Sierra Specialties resleeve a few years ago. (The original for my '33 looks a bit different from the VPW one and I wanted to return to a stock look and the MC is visible on my car with the hood open so I had it resleeved and was waiting for a "round tuit" to install it.)

 

I don't recall how much I spent to resleeve. I try not to remember how much I spend on the car. But I guess I could look it up in my records. He posts his prices on his web site though. http://www.brakecylinder.com/prices2011.htm

 

Hmmm. That page now says "We have retired and are no longer accepting work. Information on this website is presented for historical and educational purposes only." So I guess I shouldn't recommend him any more.

Looks like ti would be a 100 bucks, plus the kit, I would do the nead blast and clean myself. So re-sleeving and new would be similar in price, but a brass sleeve would be very durable...

[55 Fargo]

Not sure who you are planning to have re-sleeve your cylinder but... my master and wheel cylinders came back from Joe at Sierra Specialties looking wonderful inside and out. I don't know how he cleans them up, but bead blasting was not neccessary.

Acid dip perhaps before the sleeving?

[ggdad1951]

Can't remember if I posted already. ... back building FEF I chased a leaky wc, how many times I bled and LOTS of DOT...got a different one and no probs since....I never did figure why that one was leaky, looked and felt fine.

[55 Fargo]

Can't remember if I posted already. ... back building FEF I chased a leaky wc, how many times I bled and LOTS of DOT...got a different one and no probs since....I never did figure why that one was leaky, looked and felt fine.

I wonder if anything i did on install is causing this new wheel cyl to leak? I have to pull it again, the drum is in spec, shoes are new, brake hardware is new, but this new wheel cyl is leaking on the same side the old wheel cyl was leaking. Anybody got any ideas?

[Dave72dt]

Leaking at the fitting or inside?  two cyl per wheel or one?  single cyl per wheel, you can try switching the rubber cups from one side of the cyl to the other and recheck.  That'll tell you if it's the cyl or the cups.  It only takes a small flat spot, nick or rough spot on the rubber for it to leak or a score mark on the cyl.