Thinking of taking another crack at rebuilding a proportioning valve. Tried this years ago on the valve currently in my 66 but was a miserable failure, probably due to undetected scoring in the bore, and had to have it re-sleeved. But I'm a glutton for punishment.
I know how to do the rebuild, my question is the best way to assemble everything for longer term storage? It will likely be awhile before I install it and assume assembling with brake fluid is not the best idea if it sits awhile? Is it OK to assemble with a light coat of WD-40, Boeshield, or similar? Or would that cause an issue mixing with brake fluid when I do install? Or...should I just bag the idea for now and wait to rebuild when I'm ready to install?
Thanks,
Dave
Dave, I, too gave it a try and, like you, failed miserably. At $150 a pop, White Post Restorations did my last two. Don't know what, if anything, they coated the bores with but, if I were doing the job, I'd use a light coat of silicone brake fluid which could easily be flushed out if conventional DOT3 were to be used. The silicone is basically inert and would have no affect on the metal or rubber seals.
Quote from: s2ms on May 08, 2020, 12:46:34 PM
Thinking of taking another crack at rebuilding a proportioning valve. Tried this years ago on the valve currently in my 66 but was a miserable failure, probably due to undetected scoring in the bore, and had to have it re-sleeved. But I'm a glutton for punishment.
I know how to do the rebuild, my question is the best way to assemble everything for longer term storage? It will likely be awhile before I install it and assume assembling with brake fluid is not the best idea if it sits awhile? Is it OK to assemble with a light coat of WD-40, Boeshield, or similar? Or would that cause an issue mixing with brake fluid when I do install? Or...should I just bag the idea for now and wait to rebuild when I'm ready to install?Just my suggestion.
Thanks,
Dave
I would rebuild it with whatever brake fluid (silicone or conventional) that you plan on using. I would not use boeshield or wd 40 as it may have have a negative effort when mixed with brake fluid. Not sure how long of storage but bag the valve and a year or 2 in the sealed bag should not be a issue. People use NOS valves in a box that are decades old without issues mostly. If you decide to wait I would put the rebuild kit in a bag so it doesn't degrade. Who knows if the parts will be readily available when you are ready to rebuild years from now.
Quote from: NC TRACKRAT on May 08, 2020, 12:55:32 PM
Dave, I, too gave it a try and, like you, failed miserably. At $150 a pop, White Post Restorations did my last two. Don't know what, if anything, they coated the bores with but, if I were doing the job, I'd use a light coat of silicone brake fluid which could easily be flushed out if conventional DOT3 were to be used. The silicone is basically inert and would have no affect on the metal or rubber seals.
You are correct on the properties but I do not agree on your advice about flushing the silicone out. If you use silicone you will have to disassemble again to properly clean and re assemble with dot 3 if wanting to use the Dot 3. Same goes if you assembled it with Dot 3 and want to run silicone. When the two interact the reaction is a tendency to gel up. You may be able to flush out enough and you may not. You have to ask yourself is it really worth the gamble of contaminating your entire brake system. Do one or the other and if you change your mind disassemble ,clean and re assemble with desired brake fluid . That is my advice . Use it or not.
Quote from: NC TRACKRAT on May 08, 2020, 12:55:32 PM
Dave, I, too gave it a try and, like you, failed miserably. At $150 a pop, White Post Restorations did my last two. Don't know what, if anything, they coated the bores with but, if I were doing the job, I'd use a light coat of silicone brake fluid which could easily be flushed out if conventional DOT3 were to be used. The silicone is basically inert and would have no affect on the metal or rubber seals.
Thanks Stan. White Post also did the one currently in the car, which has worked flawlessly for at least 15 years. That one is a later service part, the one I'm thinking of rebuilding now is an OE valve with the correct machining and perfect date code.
Quote from: Bob Gaines on May 08, 2020, 01:01:08 PM
I would rebuild it with whatever brake fluid (silicone or conventional) that you plan on using. I would not use boeshield or wd 40 as it may have have a negative effort when mixed with brake fluid. Not sure how long of storage but bag the valve and a year or 2 in the sealed bag should not be a issue. People use NOS valves in a box that are decades old without issues mostly. If you decide to wait I would put the rebuild kit in a bag so it doesn't degrade. Who knows if the parts will be readily available when you are ready to rebuild years from now.
Thanks Bob, a year or 2 is about right. It'll take me that long to want to do the job badly enough since it's a bit of a PITA to do just for cosmetic reasons.
I never use brake fluid to assemble hydraulic parts. Here's why:
(https://images-na.ssl-images-amazon.com/images/I/71YmQSfiSpL._AC_SL1008_.jpg)
Quote from: Bossbill on May 08, 2020, 03:50:09 PM
I never use brake fluid to assemble hydraulic parts. Here's why:
(https://images-na.ssl-images-amazon.com/images/I/71YmQSfiSpL._AC_SL1008_.jpg)
You can also ask the people who rebuild them and warrenty them if they fail use. FYI if you have a wheel cylinder ,proportioning valve etc built at white post they will not assemble them with silicone. I have to disassemble ,clean and reassemble with silicone which is what I suggest for limited driving pleasure driven cars. At least it reassembles much easier once it is has been rebuilt . What a pain. ::)
Quote from: Bossbill on May 08, 2020, 03:50:09 PM
I never use brake fluid to assemble hydraulic parts. Here's why:
Thanks Bill, never even knew that stuff existed! Found one source that said the Centric fluid is "Compatible with all DOT 3 and DOT 4 brake fluids".
Quote from: s2ms on May 08, 2020, 12:46:34 PM
Thinking of taking another crack at rebuilding a proportioning valve. Tried this years ago on the valve currently in my 66 but was a miserable failure, probably due to undetected scoring in the bore, and had to have it re-sleeved. But I'm a glutton for punishment.
I know how to do the rebuild, my question is the best way to assemble everything for longer term storage? It will likely be awhile before I install it and assume assembling with brake fluid is not the best idea if it sits awhile? Is it OK to assemble with a light coat of WD-40, Boeshield, or similar? Or would that cause an issue mixing with brake fluid when I do install? Or...should I just bag the idea for now and wait to rebuild when I'm ready to install?
Thanks,
Dave
The biggest problem of using a non-brake fluid (either DOT 3 or silicone) petroleum-based product (like the ones that you mentioned) is the incompatibility of the rubber parts, in the proportioning valve, with the assembly fluid. Petroleum-based products will cause swelling and degradation of the rubber and ultimately failure---which is not a good thing to happen on a brake-related component.
Frank
Understand your well-founded concern but, FWIW, I've switched a couple of systems over to silicone by thoroughly flushing and had no adverse effects. Just lucky I guess.
Quote from: s2ms on May 08, 2020, 06:19:00 PM
Thanks Bill, never even knew that stuff existed! Found one source that said the Centric fluid is "Compatible with all DOT 3 and DOT 4 brake fluids".
Dave -- The stuff I have is from another vendor (Bendix?) but it's the same idea.
If the bore of the proportioning valve needs a sleeve, I use stainless. Some people use brass because it's easier, but I prefer stainless. With stainless you'll never have to worry about pitting in the bore again. Assemble with your choice of fluid, cap the ports and store in a dry place.
McKay also has brake assembly lube . Smaller semi clear bottle. Works great . Orielly's , Autozone , should have it.
Randy
Thanks to everyone for all the info!
Have the valve apart and cleaned up, generally in very good shape. The bore is also pretty good but the minor scoring is a little too much so will likely have it re-sleeved.
Quote from: KR Convertible on May 11, 2020, 10:51:30 AM
If the bore of the proportioning valve needs a sleeve, I use stainless. Some people use brass because it's easier, but I prefer stainless. With stainless you'll never have to worry about pitting in the bore again. Assemble with your choice of fluid, cap the ports and store in a dry place.
I assume brass would be resistant to pitting as well? I've read different opinions about using brass or stainless, Some say brass is less prone to leaking since it's "softer" allowing seals to seat better. Others say stainless is better because it's more durable. Other opinions?
Thanks,
Dave
(http://www.saacforum.com/gallery/236-110520123627.jpeg)
When in doubt sleeve. That is better then installing and have it leak right away or worse later. Messing up the paint with leaking conventional brake fluid is also something that would influence the decision to error on the side of caution IMHO.
I would think the rubber seal would work the same on either brass or stainless, provided the surface finish is the same. The piston in the valve moves very little, all of the wear will be in one small area, so I prefer stainless If I remember correctly, I used a 1/2" stainless plumbing nipple and machined the OD and ID to make the sleeves.
Dave ,
Mine was done with brass 30 years ago along with my wheel cylinders and they have been trouble free ever since.
BTW there are two different types of "internals" . The kits only work with the FAR more common "later" version. The "early" valve is anodized light purple (for reference).
Randy
Guys, from a "pitting" standpoint, either brass or stainless (assuming a 300-series material) is a toss up. From a "leak" standpoint, once again a toss up as far as leaking past the chevron seals in the bore. I believe that most leaks are from a void in the "glued joint" between the iron cylinder and the sleeve. The sleeves are generally installed using a Loctite-type product to PERMANENTLY affix the sleeve to the bore.
From a "machining standpoint", brass is far easier to machine/hone to size than stainless so the price to install and finish the sleeves could be reflected in the out-the door price.
I don't think that you can go wrong using EITHER material for the sleeve. As far a which type of brake fluid to use, I feel that DOT 5 is a better choice for any car that isn't a daily driver. I feel that the "pros" out way the "cons". I know that I'll probably get some push back for that statement but that's my view of the world.
Frank
Great info, thank you all!
Quote from: OldGuy on May 11, 2020, 05:10:43 PM
Guys, from a "pitting" standpoint, either brass or stainless (assuming a 300-series material) is a toss up. From a "leak" standpoint, once again a toss up as far as leaking past the chevron seals in the bore. I believe that most leaks are from a void in the "glued joint" between the iron cylinder and the sleeve. The sleeves are generally installed using a Loctite-type product to PERMANENTLY affix the sleeve to the bore.
From a "machining standpoint", brass is far easier to machine/hone to size than stainless so the price to install and finish the sleeves could be reflected in the out-the door price.
I don't think that you can go wrong using EITHER material for the sleeve. As far a which type of brake fluid to use, I feel that DOT 5 is a better choice for any car that isn't a daily driver. I feel that the "pros" out way the "cons". I know that I'll probably get some push back for that statement but that's my view of the world.
Frank
You heretic you. ;D
Guilty as charged.
Whitepost rebuilt mine 4 years ago and when I took the car out of storage this spring, there was a small puddle of fluid on the ground. I've traced it back to the rear of the prop valve, probably o-ring. I use DOT 5 and have read it can cause newer rubber to swell. Anyone else run into this and are there replacement o-rings that are better suited for this? The brake pedal is otherwise firm and doesn't go to the floor.
Quote from: sg66 on May 24, 2020, 01:31:02 PM
Whitepost rebuilt mine 4 years ago and when I took the car out of storage this spring, there was a small puddle of fluid on the ground. I've traced it back to the rear of the prop valve, probably o-ring. I use DOT 5 and have read it can cause newer rubber to swell. Anyone else run into this and are there replacement o-rings that are better suited for this? The brake pedal is otherwise firm and doesn't go to the floor.
I am surprised that you had that type of o-ring failure using DOT 5 fluid. I wouldn't have been as surprised if you were using DOT 3 or 4 fluid. DOT 5 fluid is a very "inert" fluid that is reasonably compatible with many o-ring materials. Having said that however, the recommended o-ring material for either glycol-based (DOT 3 and 4) or silicone-based fluid is ethylene propylene (EPDM). This information was taken from the Parker Hannifin O-ring Handbook.
I hope this helps.
Frank
Quote from: OldGuy on May 24, 2020, 02:36:47 PM
Quote from: sg66 on May 24, 2020, 01:31:02 PM
Whitepost rebuilt mine 4 years ago and when I took the car out of storage this spring, there was a small puddle of fluid on the ground. I've traced it back to the rear of the prop valve, probably o-ring. I use DOT 5 and have read it can cause newer rubber to swell. Anyone else run into this and are there replacement o-rings that are better suited for this? The brake pedal is otherwise firm and doesn't go to the floor.
I am surprised that you had that type of o-ring failure using DOT 5 fluid. I wouldn't have been as surprised if you were using DOT 3 or 4 fluid. DOT 5 fluid is a very "inert" fluid that is reasonably compatible with many o-ring materials. Having said that however, the recommended o-ring material for either glycol-based (DOT 3 and 4) or silicone-based fluid is ethylene propylene (EPDM). This information was taken from the Parker Hannifin O-ring Handbook.
I hope this helps.
Frank
I was reading on a Corvette forum that back in 2015, the EPA changed manufacturing regulations which may have effected rubber parts. I can't find the original thread but this is what they were referring to.
Corvette Stainless Steel Brakes voids warranty if silicone fluid is used: http://cssbinc.com/dot5warrantynew.01.pdf
Links to EPA page: https://www.regulations.gov/document?D=EPA-HQ-OPPT-2009-0767-0031
What a disappointing dvelopement.
Quote from: sg66 on May 24, 2020, 03:38:47 PM
Quote from: OldGuy on May 24, 2020, 02:36:47 PM
Quote from: sg66 on May 24, 2020, 01:31:02 PM
Whitepost rebuilt mine 4 years ago and when I took the car out of storage this spring, there was a small puddle of fluid on the ground. I've traced it back to the rear of the prop valve, probably o-ring. I use DOT 5 and have read it can cause newer rubber to swell. Anyone else run into this and are there replacement o-rings that are better suited for this? The brake pedal is otherwise firm and doesn't go to the floor.
I am surprised that you had that type of o-ring failure using DOT 5 fluid. I wouldn't have been as surprised if you were using DOT 3 or 4 fluid. DOT 5 fluid is a very "inert" fluid that is reasonably compatible with many o-ring materials. Having said that however, the recommended o-ring material for either glycol-based (DOT 3 and 4) or silicone-based fluid is ethylene propylene (EPDM). This information was taken from the Parker Hannifin O-ring Handbook.
I hope this helps.
Frank
I was reading on a Corvette forum that back in 2015, the EPA changed manufacturing regulations which may have effected rubber parts. I can't find the original thread but this is what they were referring to.
Corvette Stainless Steel Brakes voids warranty if silicone fluid is used: http://cssbinc.com/dot5warrantynew.01.pdf
Links to EPA page: https://www.regulations.gov/document?D=EPA-HQ-OPPT-2009-0767-0031
Wow, talk about "light reading"
Quote from: sg66 on May 24, 2020, 01:31:02 PM
Whitepost rebuilt mine 4 years ago and when I took the car out of storage this spring, there was a small puddle of fluid on the ground. I've traced it back to the rear of the prop valve, probably o-ring. I use DOT 5 and have read it can cause newer rubber to swell. Anyone else run into this and are there replacement o-rings that are better suited for this? The brake pedal is otherwise firm and doesn't go to the floor.
Did you flush the valve after getting it back from White post? Confirmed recently they assembly and test their rebuilds using Dot 3.
Quote from: s2ms on May 24, 2020, 06:03:04 PM
Did you flush the valve after getting it back from White post? Confirmed recently they assembly and test their rebuilds using Dot 3.
Yes I did take it apart and clean it before adding DOT5. All lines and rear cylinders were new, Jim Cowles did the front calipers for DOT5 and the MC was cleaned and previously had DOT5 for 25+ years.
The vette thread I was looking at is: https://www.corvetteforum.com/forums/c1-and-c2-corvettes/3887928-how-risky-is-using-dot-5-a.html
It seems that WhitePost and LoneStar both say the silicon fluid is not compatible with "
their" seals which brings me back to who makes seals and o-rings that are still compatible with silicon fluid?
I know Scott Drake makes a kit but can't find any info on the material used or compatibility with DOT5.
Another good thread with o-ring and seal specs: https://www.allfordmustangs.com/forums/classic-tech/1035929-66-gt-proportional-valve-issues.html
I plan to pull it apart this week to see whats going on and measure the seals before they have a chance to dry.
I don't have a degree in chemical engineering, just one in industrial engineering, but I find it difficult to envision a fluid that won't harm paint would affect rubber o-rings. The proportioning valve in 6S1467 was re-built by White Post and has been in service for a number of years with no adverse effect noted.
Quote from: gt350hr on May 11, 2020, 04:13:37 PM
BTW there are two different types of "internals" . The kits only work with the FAR more common "later" version. The "early" valve is anodized light purple (for reference).
Randy
Circling back on this to share what I found and also ask Randy what in the kits doesn't work with the early purple anodized valve which is what I have?
1.) Inside clearly had signs of rust on the un-sleeved part of the cylinder which started to find its way past the rubber o-ring on the end cap. How moisture found it's way in is a mystery.
2.) According to Parker Hannifin, o-ring materials react differently with DOT3, 4 or 5 and EPDM is recommended for all. Most o-rings like Danco sold in hardware stores are Nitrile (NBR)
3.) I don't know what White Post uses but the o-ring on the end cap had a thickness of 0.0955". For comparison, a #17 Danco measures around 0.1025". I bought 119-E70 EPDM 70 o-rings which are around 0.1050".
4.) These measurements don't sound like much but the cast iron where the o-ring sits has some minor pitting. Machining that smooth would open the gap to fill with the o-ring and in the end likely create a bigger leak.
5.) The final piece is the c-clip on the end. The one from White Post measured 0.0500". For comparison, I bought a few at Ace that ranged from 0.0500 to 0.0520". This matters because when the adjusting screw and spring are tightened, they want to push the end cap away from the body and reduce the sealing potential of the o-ring.
6.) Between the o-ring and c-clip I reduced the area to be sealed by around 0.0115" (between the red and blue lines)
Back to Randy's comment, mine is the earlier valve so the o-rings mentioned and measurements may not be relevant for later valves.
Also FWIW, I bought some extra EPDM and Nitrile o-rings and soaked each in DOT 5 and DOT 3 for a week and the only measurable swelling was the Nitrile rings in DOT 3.
Steve-
Steve ,
IIRC there is one O ring in the later kit that doesn't work on the early valve. It's been a few years since I had another sleeved and I now have lost my source for sleeving altogether.
Randy
Thanks Randy
I'll leave this here for future reference. White Post uses a 1.00" and 0.70" OD lip seal on the earlier purple valves. FWIW, this valve is stamped 267-5