TR2/3/3A Recommended brake fluid for a 3A?

[GTP1960]

First: Is bleeding & Replacing your brake fluid an annual thing?
Or as needed?


I'm not having any problems with clutch or brakes, but the fluid in the res. is a putrid muddy gray color.

Also, any advantage to going to DOT5, over 3-4?

your help is appreciated!

best regards

Guy

 

[Geo Hahn]

Hoo boy, here we go.

I use DOT 5 for all the usual reasons.

Others will not use DOT 5 for all the usual reasons.

One thing we can all agree on (from your description) is that to need to thoroughly flush and fill with something out of a new brake fluid bottle.

 

[Marvin Gruber]

Guy,
with an existing, working system just stay with the dot 3/4. Lot of work to change out to dot 5. Keep the resv topped off and drive. When it time to rebuild everything then go 5,

marv

 

[TR3driver]

DOT 3/4 needs to be changed occasionally, although there is little agreement on how often. It absorbs moisture from the air and deteriorates over time. (This is why it's so important to open a fresh bottle, as the same thing happens with an opened bottle sitting on the shelf). That muddy gray color means it is already corroding the inside of your brake cylinders, which will eventually cause them to leak. I doubt it's an issue in SC, but in more northern climes it can even absorb road salt, right through the rubber brake lines, making it even more corrosive.

DOT 5 is much closer to being "forever", both fluid and seals. I use it in all my Triumphs. My opinion, it is worth converting just because you need a fluid change. While "best practice" is probably to replace all the seals and soft lines, plus purge the system with solvent and air; I have done several now by just bleeding at all 4 corners until I get clear purple fluid. The brake problems don't immediately drop to zero, but at least in my experience, become a lot less frequent. And you immediately get the benefit that any leak will no longer destroy any paint it touches.

Here's a nicely researched article from a Triumph viewpoint https://www.buckeyetriumphs.org/technical/Brakes/Fluid/Fluid.htm
and here are copies of the two SAE papers referenced in the above article
https://drive.google.com/open?id=0B2H2NJt34OffdnhWS19scjlNUU0

 

[GTP1960]

DOT 5 is much closer to being "forever", both fluid and seals. I use it in all my Triumphs. My opinion, it is worth converting just because you need a fluid change. While "best practice" is probably to replace all the seals and soft lines, plus purge the system with solvent and air; I have done several now by just bleeding at all 4 corners until I get clear purple fluid. The brake problems don't immediately drop to zero, but at least in my experience, become a lot less frequent. And you immediately get the benefit that any leak will no longer destroy any paint it touches.

Hey Randall,
thx for the insight. I definitely want to switch to 5 before my seals & hoses get any worse. They don't look prehistoric, so I'd like to save them, if I can. Can you tell me what solvent would work best?
also do I need a vacuum bleeder system?
I have read (& youtubed ) that you should start at furthest brake from Res & work to nearest.
then do the clutch.
any more tips appreciated, as I haven't done this in over 40 yrs.

thx to all. Appreciate your responses.

 

[CJD]

I would not recommend any solvents in the brake system. If even the tiniest bit remains in the system, it will boil at relatively low temps and you'll lose your brakes. Each hose and pipe connection is a potential trap. If you do not plan to take it all apart to individually blow the solvent out, it's best to just use air.

 

[MichaelG]

I made the change to DOT 5 by blowing the lines clear with compressed air....and of course don't flush that old fluid in the M/C through the system...first remove it with something like a turkey baster and wipe/blow out the reservoir. This is a great opportunity to change over to stainless steel brake hoses from stock rubber hoses. With the hoses off you can get all the old fluid out of the calipers and wheel cylinders. I really noticed a firmer pedal with the SS hoses.

 

[TR3driver]

Can you tell me what solvent would work best?

Don't know if it is "best", but I was told to use methanol (aka wood alcohol) many years ago. When I did my former TR3A (back around 1985 or so), I was able to buy a bottle of methanol at the local drug store; but had to ask the pharmacist for it and explain why I wanted it. Not sure if that is still the case today or not. The stuff is fairly poisonous (1/4 cup is usually fatal, lower doses can cause blindness), so treat it with respect, try to avoid getting it on your skin and so on. If you do get it on you, be sure to wash immediately. Probably any commercial "brake cleaner" would work just as well (but many of them are mostly methanol anyway so the same precautions apply).

The solvent is only for the lines, I wouldn't run it through the calipers & cylinders unless you plan to then disassemble them. Of course the lines have to be dried thoroughly afterwards. As John said, you sure don't want any liquid alcohol left in the system when you are done, not even a drop.

also do I need a vacuum bleeder system?

I've never had any luck with using vacuum bleeders, so I'd say it is certainly not required. Usually I've been able to bribe the wife or a neighborhood kid into helping me do it the old fashioned way (open the valve, push the pedal, close the valve, release the pedal). Last time around though (when assembling the TR3), I bought some speed bleeders for the rear wheels and gravity bled the front calipers. Worked out well and even with a trip to FLAPS for the bleeders, I had the brakes together and working before the wife got home. Sorry, I don't recall the size offhand, but here's a shot just to show what I mean

https://www.summitracing.com/parts/rus-639530

 

[KVH]

Assuming no change to Dot 5, I am trying to recall whether Dot 3 or Dot 4 is best for a TR4. I know it's an old subject, but one last time please? I seem to recall it's Dot 4.

 

[bobhustead]

I'm with Randall on the dot 5. When your master starts to leak, and it will, no paint damage will event. I changed 2 years ago after repainting my left firewall. The instructions on my bottle said to add and bleed until you see purple. I did it that way and have had no problems.
Bob

 

[GTP1960]

I ended up using valvolene DOT 3/4. My lines & master are all fairly new & a Moss paper ( see link below) stated that a full parts rebuild would be in order to go to DOT 5, due to even the smallest amount of old fluid remaining turning into a contaminated sludge. (could be another method to increase brake part sales, but it confirmed what Marv & CJD pointed out). I will plan on DOT 5 conversion, when the car dictates.
I borrowed a vacuum bleeder from advance auto, but it didn't work. It would create a suction while testing, but would not draw any fluid from the nipple for some reason. So I ended up using the hose & 1/2 full bottle method, pressing the pedals with a broom handle.

https://www.mossmotors.com/graphics/products/PDF/220-410.pdf

The old fluid was pretty ugly. But the brakes & clutch feel a lot better now.

thx again.

 

[Geo Hahn]

Assuming no change to Dot 5, I am trying to recall whether Dot 3 or Dot 4 is best for a TR4...

DOT4 has a higher boiling point so that would have the edge over DOT3.

That said, I have used DOT5 for the past 15 years or more w/o any problems. I just use Randall's 'ghetto' method - suck the reservoir nearly dry, fill with DOT5 and watch for purple as I bleed each corner.

Never had good results with a vacuum bleeder but have had success with a simple homemade pressure bleeder when I have difficulty getting a dry system to start to bleed.

I still finish up with a pedal bleed as that seems to me to be the surest way to get it done right.

 

[GTP1960]

That said, I have used DOT5 for the past 15 years or more w/o any problems. I just use Randall's 'ghetto' method - suck the reservoir nearly dry, fill with DOT5 and watch for purple as I bleed each corner.

thx Geo.
fifteen years! Now that is impressive results. How often do you bleed or do a complete flush?
have you had to rebuild or replace hydraulic parts?

 

[TR3driver]

thx Geo.
fifteen years! Now that is impressive results. How often do you bleed or do a complete flush?
have you had to rebuild or replace hydraulic parts?

My previous TR3A went some 30 years (approx 1985 to 2005) with DOT 5. I never flushed or bled just because the fluid was old. I did have some hydraulic problems in that length of time, mostly I remember the rubber line to the rear axle failed internally (causing it to act like a check valve) and I rebuilt the rear slave cylinders twice before figuring out what the problem was. I also kept the old worn and pitted master cylinders, which always leaked a bit (like top the fluid up twice a year or so). Also managed to spill a lot of fluid when the taper pin in the clutch broke. (Found I could get the clutch to work by pumping up the pedal, but when it was released it blew fluid against the vent hole in the reservoir lid, which would escape through the vent.)

Those calipers that I rebuilt back then are still in use today, I moved them to the current TR3 without touching the seals. Amazingly, the bleed valves opened easily even after all those years.

Another anecdote : When a caliper on my 1980 Chevy started leaking in 1988, I converted it to DOT 5. I never touched the hydraulic system again; the car went to the junkyard in 2005 with all original hoses and seals (except the one caliper that got replaced of course).

 

[Geo Hahn]

No particular problems other than what one would expect from old rubber parts - certainly nothing I could attribute to DOT5.

My previous TR3A went some 30 years (approx 1985 to 2005) with DOT 5...

Well, it sure seemed liked 30 years

 

[TR3driver]

Well, it sure seemed liked 30 years

D'oh !

 

[GTP1960]

No particular problems other than what one would expect from old rubber parts - certainly nothing I could attribute to DOT5.



Well, it sure seemed liked 30 years

Just the opposite for getting older:

the last 30 sure seemed like 20...