Seals and DOT 5.....

[ptwothree]

Anyone know of any wheel cylinder kits that are compatible with DOT 5 fluid?  Who makes 'em.  NAPA says theirs do not.

[Plymouthy Adams]

read the below link..good info..tell the reason for the each and the myths assume with changing over and how flushing will do as much damage as so-mingling the fluids themselves...if any single item is left over from the Dot 3 and you go to Dot 5 you can have trouble...if you flush with alcohol or mineral spirits as stated..major error...unless all components are new...it would be my best advice to stick with the Dot 3....

 

anyway, good reading...much more on the difference if you look online..good talking papers....

 

 

 

http://www.xs11.com/xs11-info/tech-tips/maintenance/brakes/23-the-great-dot-brake-fluid-controversy.html

[ptwothree]

Thanks for the article Tim.  My latest problem is sticking brakes that release the 4 wheels at different times.  I'm thinking that it's incompatibility of the whl cyl seals and dot 5 that has caused the seals to swell up.  Although no sings of this has occurred with the master that has a NAPA kit in it. The car has been sitting in the garage for the last 4 years (I'm slow) with dot 5 installed about a year ago.

 

If I can't get this resolved, then I'll install new kits and flush the lines and go to dot 3

[desoto1939]

I pt dot 5 in my 39 Desoto back in 88.  I rebuild the master cylinder and all wheel cylinders with new rubber components at that time. I flushed the entire system and lines with denatured alcohol.  I have not had any issues with sticking brake rubber cups. And the system has been in place for 25 years.

 

Rich HArtung.

 

If the prior ownere used Dot5 five and you car has been sitting I would start by pumping the brakes to get everything moving gain and then check for leaks.  These systems are slow to release the pressure but I had not had any issues.

[ptwothree]

I pt dot 5 in my 39 Desoto back in 88.  I rebuild the master cylinder and all wheel cylinders with new rubber components at that time. I flushed the entire system and lines with denatured alcohol.  I have not had any issues with sticking brake rubber cups. And the system has been in place for 25 years.

 

Rich HArtung.

 

If the prior ownere used Dot5 five and you car has been sitting I would start by pumping the brakes to get everything moving gain and then check for leaks.  These systems are slow to release the pressure but I had not had any issues.

 

I have replaced everything in the hydraulic circuit before installing the dot 5.  I'm going to check out the residual valve in the m/c tomorrow with the hope I assembled it backward or something.  If I crack a bleeder screw after lock up, brakes instantly release.  I found another posting in the search engine that has nice pics of the m/c parts and how they go together.  The drawing in the shop manual isn't very clear and doesn't deal with after market parts.

 

But hey Rich...it'a good to hear that this should work once the bugs are worked out.  Thanks....Gerry

[Floydflathead]

I've used DOT 5 on all my old cars without any issue for 15 years.  Of course rebuilt master/wheel cylinders and carefully cleaned out or replaced the brake lines.  If you want to keep rebuilding them and replacing damaged components due to leakage, go ahead and keep using DOT 3.

 

Tim

[ptwothree]

I've used DOT 5 on all my old cars without any issue for 15 years.  Of course rebuilt master/wheel cylinders and carefully cleaned out or replaced the brake lines.  If you want to keep rebuilding them and replacing damaged components due to leakage, go ahead and keep using DOT 3.

 

Tim

Exactly what I'm trying to avoid.

[desoto1939]

Anyone know of any wheel cylinder kits that are compatible with DOT 5 fluid?  Who makes 'em.  NAPA says theirs do not.

 

 

What year is your car.  I have a several Brake catalogs and I might have an exploded view of your master Cylinder.

 

Let me know and if I do then i will scanit and send it to your home email.  Send me you home email address.

 

Rich HArtung

desoto1939@aol.com

[ptwothree]

What year is your car.  I have a several Brake catalogs and I might have an exploded view of your master Cylinder.

 

Let me know and if I do then i will scanit and send it to your home email.  Send me you home email address.

 

Rich HArtung

desoto1939@aol.com

Thanks Rich....It's a '51 P23    Email:  voongmc@gmail.com      Thanks for your help!!

[Floydflathead]

I did have trouble with a few of the pressure sensor type brake light switches such as the master cylinder on my 1960 Dodge Dart.  Sometimes, DOT 5 can cause those to fail, although I had the same one on there for 10 years now without failure.  That is the only downside I've seen.  It is a lot easier to replace one of those than cleaning up ruined linings, re-honing, etc.  And dealing with teh Wagner Lockheed single piston cylinders on the front wheels are not something I want to have to deal with frequently!  For mechanical brake swiches on the old cars, I really can't think of any advantage to using the DOT 3 anymore.  I've heard many claims about the chemical makeup not workign correctly with the rubber cups on the wheel cylinders, but have never seen any of these problems in practice -- no leaks at all, yet a 1940 Plymouth coupe that I replaced all the wheel cylinders and master cylinder has lost brakes, because I used DOT 3 in that system when I restored it years ago.  If you drive your car everyday, and live in a fairly dry climate, DOT 3 is probably fine, but any periods of inactivity will surely have the brake fluid gathering water/moisture with the resulting corrosion and leakage.  Alcohol is hygroscopic (absorbs water).  The other good news if you drip some DOT 5 fluid accidentally on your paint when you're filling (you almost never would have to do that compared to frequency with DOT 3), you won't ruin your paint.  Anyway, that's my experience for what it's worth.

[ptwothree]

I did have trouble with a few of the pressure sensor type brake light switches such as the master cylinder on my 1960 Dodge Dart.  Sometimes, DOT 5 can cause those to fail, although I had the same one on there for 10 years now without failure.  That is the only downside I've seen.  It is a lot easier to replace one of those than cleaning up ruined linings, re-honing, etc.  And dealing with teh Wagner Lockheed single piston cylinders on the front wheels are not something I want to have to deal with frequently!  For mechanical brake swiches on the old cars, I really can't think of any advantage to using the DOT 3 anymore.  I've heard many claims about the chemical makeup not workign correctly with the rubber cups on the wheel cylinders, but have never seen any of these problems in practice -- no leaks at all, yet a 1940 Plymouth coupe that I replaced all the wheel cylinders and master cylinder has lost brakes, because I used DOT 3 in that system when I restored it years ago.  If you drive your car everyday, and live in a fairly dry climate, DOT 3 is probably fine, but any periods of inactivity will surely have the brake fluid gathering water/moisture with the resulting corrosion and leakage.  Alcohol is hygroscopic (absorbs water).  The other good news if you drip some DOT 5 fluid accidentally on your paint when you're filling (you almost never would have to do that compared to frequency with DOT 3), you won't ruin your paint.  Anyway, that's my experience for what it's worth.

 

It's worth a lot. The exchange of ideas, thoughts, experience etc. is what forums like this are about.   After considering all the opines concerning the good and bad of dot 5. I'm going to give it a whirl and see what happens.

 

Anyway, I took the end plug off the m/c today and found the residual valve cocked at an angle, about an 1 1/2" inside the bore.  I reassemble everything and backed off the adjusters and the m/c push rod and bleed it.  The right front is the only one hanging up now soooooooo.....I guess I'll put new kits in that wheel and see what happens. I think once that is fixed and everything is readjusted, all should be good.  More later!

[TodFitch]

It's worth a lot. The exchange of ideas, thoughts, experience etc. is what forums like this are about.   After considering all the opines concerning the good and bad of dot 5. I'm going to give it a whirl and see what happens.

 

Anyway, I took the end plug off the m/c today and found the residual valve cocked at an angle, about an 1 1/2" inside the bore.  I reassemble everything and backed off the adjusters and the m/c push rod and bleed it.  The right front is the only one hanging up now soooooooo.....I guess I'll put new kits in that wheel and see what happens. I think once that is fixed and everything is readjusted, all should be good.  More later!

Sounds like you have DOT3 in there now. Did you read the article at the link Plymouthy Adams posted?

 

Whatever the merits of one type of fluid over the other, the actual process of changing from one type to the other is an issue. Comes down to two major things:

 

1. They are two different densities, the DOT5 will float on top of the DOT3 in the wheel cylinders. Because the bottom of the cylinders is below the bleeder you will never get out all the old DOT3 by simply filling and bleeding with DOT5.

 

2. Use of a alchol or petroleum based fluid to the "flush" the old fluid out will damage the rubber componets.

 

Basically what it comes down to is you decide what fluid you are going to use when you do a full replacement of all hydraulic components in the brake system including all the tubing and hoses after that you keep using what you started with.

[De Soto Frank]

FWIW - I did a complete brake system rebuild on my '41 De Soto back in 1988.  I replaced all wheel cylinders and the master cylinder ( all were NORS, with fresh "rubber" cups [Wagner]).

All steel liens were replaced, as were the flex hoses.  The only re-used parts were the brake pedal and the backing-plates & drums.

 

I used DOT-5 slilcone fluid, based on its resistance to absorbing moisture from the atmosphere.

 

I had two issues:

 

1)  Unwittingly, I completely frothed / foamed the fluid by filling / bleeding the system with an old-time pressure bleeder ( no diaphragm to keep the fluid and the air separate).  Took me several phone calls to the fluid manufacturer's tech support to figure this out.   Tech suggested letting system sit over night with the Mc filler cap removed, then GENTLY pedal bleed, and when necessary to add fluid, do so slowy and carefully, to avoid aerating the fluid.

 

 

2)  Hydraulic stoplight switches:  I replaced the orignal switch with a new one from KEM, to avoid any possibility of fluid contamination.   After about two months, the switch failed,  I replaced it with another KEM switch, and that one failed after about two months.  The next switch was from Standard / Blue-Streak.  That one failed after 2-3 months.   In each case, the failure manifested itself by requiring increasing amounts of foot pressure on the brake pedal to close the switch, eventually far exceeding the amount of pedal pressure necessary to stop the vehicle.

 

I decided to abandon the pressure switch, in favor of a "Chevrolet-style" mechanical switch, that mounts to the underside of the toe-board, and employs a mechanical "finger" that rides the brake pedal arm.

 

Once the stoplight-switch issue was resolved, the system has been trouble free since ( 15 years / 40,000+ miles ).

Edited September 23, 2013 by De Soto Frank

[ptwothree]

My car has had nothing but dot 5 in it since I replace the hydraulics over a year ago.  I was toying with the idea of changing to dot 3 in the event that there would be swelling of the seals as a result of the dot 5.  I installed Dorman (Chinese) wheel cylinders and a NAPA kit for the m/c as the PO did a stainless sleeve on it.  I suspect something is not right with the right front as it is still hanging up.  Cracking either one of the bleeders will cause fluid to shoot out and the brakes in that wheel will release.

 

None of the other wheels has this problem so I can only assume there is something going on with the wheel cyls 

[TodFitch]

My car has had nothing but dot 5 in it since I replace the hydraulics over a year ago.  I was toying with the idea of changing to dot 3 in the event that there would be swelling of the seals as a result of the dot 5.  I installed Dorman (Chinese) wheel cylinders and a NAPA kit for the m/c as the PO did a stainless sleeve on it.  I suspect something is not right with the right front as it is still hanging up.  Cracking either one of the bleeders will cause fluid to shoot out and the brakes in that wheel will release.

 

None of the other wheels has this problem so I can only assume there is something going on with the wheel cyls 

I've never had this symptom so I can't say from personal experience but I've heard that a bad hose that has swollen shut can cause this. The master cylinder has enough pressure to force fluid through but the return springs on the brake shoes aren't strong enough to push the fluid back.

[Tom Skinner]

I guess I'm an idiot.

I have always used DOT 3, and every few years just flushed/bled my system with new DOT 3 to keep my brake fluid clear/clean.

My brakes adjusted and fluid (DOT3) clear all systems working fine.

Once again the old fashioned maxim "If it ain't broke don't fix it" comes to mind. Why would anyone want to put themselves through

the expense and work to change out all boots, and piston seals etc and flush a system to go over to DOT 5?. Crap that's gotta be like

flushing money down the toilet. Or better yet just throw it down a rat hole, No better - just mail it to me - I could make good use of it somehow.

L.O.L.

[desoto1939]

Mike:  When my brakes went in my old 39 Desoto and it had the old Dot 3 fluid I spoke to a good Mopar Mechanic and he stated to go to Dot5.  I started by flushing the Master Cylinder and filled it wil denatured Alchol. Then flushed the entire metal brake lines and wheel cyl's.

 

Then installed the new inner parts to the brakes. Then install the DOT5 and keep bleeding the lines until I had only the purple DOT5 brake fluid in the overfill container.

 

That was done in 1987  and still have the original inner brakes parts and brake hoes in place without any issues.

 

To me it was worth the effort. But the world is made up of all types of people so I took that route. Bad or indifferent.

 

Rich HArtung

desoto1939@aol.com

[ptwothree]

the latest.....  Took the right front cyls apart.  After taking out the pistons I noticed the fluid left behind had a kind of goopy texture.  Probably a mix of assembly lube and the brake fluid.  Also found some small black particles inside as well.

 

I noticed that the pistons are on piece.  The stockers are two piece and I think that is what the rebuild kits are for.  Can't see getting a new seal over a one piece piston.  I could be wrong, but, I think that's how these things are made these days.  I'll just clean it up and re-install and bleed tomorrow.

 

Tom....I'm with you....I wouldn't go through all this for a different fluid unless I was replacing all the hydraulics.  In this case, that's what I've done.

[De Soto Frank]

I guess I'm an idiot.

I have always used DOT 3, and every few years just flushed/bled my system with new DOT 3 to keep my brake fluid clear/clean.

My brakes adjusted and fluid (DOT3) clear all systems working fine.

Once again the old fashioned maxim "If it ain't broke don't fix it" comes to mind. Why would anyone want to put themselves through

the expense and work to change out all boots, and piston seals etc and flush a system to go over to DOT 5?. Crap that's gotta be like

flushing money down the toilet. Or better yet just throw it down a rat hole, No better - just mail it to me - I could make good use of it somehow.

L.O.L.

 

 

 I wouldn't have done it either, except many of the per-War cars (including my '41 De Soto) have Step-bore wheels cylinders that are either hideously expensive, or unobtainable.

 

( They aren't available for cheap from Rock Auto like those for the post-war MoPars.)

Sleeving these SOB's is twice as expensive as for single-bores, as there is a spearate bore & sleeve for each diameter bore in the same casting.

 

So, the idea of finding a brake fluid that does NOT absorb moisture from the atmosphere ( DOT-3 and DOT-4 still do this) and destroy the expensive bits is attractive, at least on the face of it.

 

 

That said, i have done several full-system brake rebuilds since going the DOT-5 route with my De Soto, and each one of those has gotten DOT-3 or DOT-4.

 

I can count on the fingers of one hand, the number of people that I know of (including yourself) who routinely flush and refill their DOT-3/4 brake systems as part of their PMs on their vehicles.

 

(Not saying that it is not necessary, or that it is not a good idea;  just stating that damned-few people do it.)

 

 

PTwoThree:   The rubber rings stretch-over the one-piece grooved pistons.  Warming the pistons first in warm water or similar makes them more flexible.

 

If you are having fluid squirt-out of a bleeder w/o pressure on the brake pedal,  that suggests a blocked / restricted flex-hose, and/or blocked compensating port in the floor of the MC reservoir, and/or insufficient free-play between the push-rod and the piston of the Master Cylinder ( preventing piston from returning all the way agaisnt the internal stop, and clearing the compensating port.

 

Good luck !

 

De Soto Frank

[Tom Skinner]

I guess I wasn't very charitable.

Look if your brakes are toast and you have to overhaul them, I guess DOT 5 is a good option.

The 1948 Royal's I have owned didn't need anything but bleeding once in a while (They were and are low mileage 1948 Chrysler's).

I have replaced cups and boots at master cylinders, and lines and shoes, but I was too lazy to go all out to DOT 5

when it didn't seem to warrant it. I am real careful when bleeding not to let DOT 3 near my paint.

Well good luck fellows, I admire your tenacity.

Tom

[De Soto Frank]

Tom,

 

 I cut my MoPar teeth on a '48 New Yorker during my last year of college, back in 1988-89;  there were no interwebs then, nor handy-dandy helpful forums like this one, so I was really wandering in the wilderness... occasionally, I 'd hook-up with an old-timer who knew his stuff and would give me accurate & useful advice, but most of the time, it was just me, the Chrysler, a photo-copied Chrysler  shop manual, and a lot of head scratching, trial and error.

 

Fortunately, all the brake parts were available at local Mom & Pop auto-stores, and I even had a local shop that still relined brake shoes...  my biggest headache back then was trouble-shooting the M-5 semi-automatic.

 

Fast forward to 1997, when I picked-up the '41 De Soto, I figured, "oh the brakes will be easy, just like the ones on my NYer..."  that was when I discovered the joys of the pre-Wwar MoPar and its step-bore wheel cylinders...

Since that job, I've redone about six or seven brake systems, all on later stuff, and have NOT used DOT 5...  I really couldn't justify the expense.

Fortunately, the De Soto's brakes have behaved since the initial debacle with the pressure bleeder, and the stoplight switch issue.

 

I wish I had my sh*t together well-enough to be flushing my DOT-3/4 systems every 3 to 5 years... LOL 

 

[Grdpa's 50 Dodge]

My 50 needs all after setting for 40 years.  I have never had any luck with cyl kits(and havent yet removed what I have to assess condition now).  Guessing not great after 40 year nap.

 

I read that link up top what scares me it sounds as if dot 5 isnt the end all they thought is was going to be.  "IF" they go away and quit dot 5 ALL brake parts that are wet says have to replace.

 

Also scary is short effective life of rust prevents in dot 3.  Is dot 4 better in rust water prevent???

 

I was going ALL new components and going dot 5 for the water issue,,,now thinking dot 3 or 4 and trying to replace fluid every few years.

 

It would help tons to have a power bleeding /flushing tool like now days,,,also a hoist for this old goat to work under.!!!  Dont buy lottery tickets so those are out!!!

 

Was even suggested, probably a good idea, to can the drums and go disc brake conversion.    Does that influence the dot 3/4 vs 5  selection.  Are calipers more tolerate than wheel cyl.???  No hot rodding here

 

At this point I can be swayed any direction.  Sway me please!!!

[Young Ed]

The biggest point for me is are you going to drive it. I've had dot 3 in both of mine for years. One about 13 and the other almost 10. I've not had to tear back into them. A disk brake conversion wouldn't sway me towards dot 5 either. I don't believe new cars have switched to it so those parts would have been using 3 from the factory.

[knuckleharley]

IMHO,the two advantages DOT 5 has over DOT 3 is it won't eat paint,and the fact that it doesn't cause rust in your lines is a bonus for cars you only drive once a year.

 

People drive cars with DOT 3 in their brake lines for 20 years or more without ever flushing and changing the fluid. In fact,I am the only one I know that flushed out a working system to get water out of it. I just used DOT 3 and kept filling and flushing until clean new brake fluid started coming out all the bleeders on a 73 Dart I had bought that looked like it had motor oil instead of brake fluid in the master cylinder.

 

Seems to me the water from condensation isn't much of threat in cars driven regularry because the fluid gets hot enough to eliminate the water if you drive it much. That's just a guess because the only time I have ever seen rust inside  wheel cylinders or a master cylinder was in cars that had sat for years.

[Plymouthy Adams]

for all the pros and cons I have no intentions of moving form Dot 3 to Dot 5 and never has this ever been a real pushed moved except in the motorcycle world for some reason...the only time I ever put Dot5 in a system was my Norton 850 Commando when I rebuilt the brakes...BUT...as  note then and not so sure now if the same..but the dye in the Dot5 would stain the plastic reservoirs and give a false indication of full reservoir on opaque see through type reservoirs.  Thought the creation of the Dot5 was the brain child of the Army who commissioned DuPont to create a fluid for certain theatres of operation it has such been look at yet again and has created yet another blend Dot 5.1

 

Not sure if or how many actual car makers has this as stock component..could not find a list through an internet search..and only a reference to H.D. who does use the Dot 5 and there are a number of cautions on its use and handling on servicing in the owners/maintenance manuals..

Edited September 25, 2013 by Plymouthy Adams