Brake fluid

[Rut]

I'm going to use Dot 5 silicone brake fluid in a new system and wondered if anyone has a brand they like? This will be in a Sierra sleeved Bugeye MC.
Thanks, Rut

 

[SD Bugeye]

I didn't like the 'pedal feel'of the stuff
we were messing around in the hills "play chase "
and came to a turn the vette in front of me didnt like and he braked hard
I mashed to stop pedal as I did the pedal felt soft!
didnt like that ....it stopped all even nothing to dramatic it I just didn't like it .
its not for me

 

[Rut]

I didn't like the 'pedal feel'of the stuff
we were messing around in the hills "play chase "
and came to a turn the vette in front of me didnt like and he braked hard
I mashed to stop pedal as I did the pedal felt soft!
didnt like that ....it stopped all even nothing to dramatic it I just didn't like it .
its not for me

I understand that it's tough to get all the air bubbles out of dot 5 and probably doubly tough since it's a Bugeye, but I've had the opportunity to drive an MGB with dot 5 and it felt just like my MGB. Along with a dot 5 recommendation can anyone give me a personal experience using Evans waterless coolant?
Thanks, Rut

 

[dklawson]

My experience is not Bugeye related but I have DOT-5 in all my British cars. I will share the following comments and recommendations.

• Change ALL the rubber in the system. All of it. That includes the hoses and any components like proportioning valves.
• Always rebuild the cylinders (master and wheel) with new rubber.
• Fit stainless braided brake hoses when you replace the rubber ones. (The pedal will be firmer).
• Flush the metal lines with isopropyl alcohol. Rinse several times and blow through with compressed air to dry the lines. Don't rush.
• When filling the reservoir, put the CLEAN blade of a screwdriver in the opening to the reservoir and rest its tip on the bottom. Slowly pour the brake fluid against the screwdriver blade/shank from a close distance. The fluid will flow down the blade and fill the reservoir without splashing or making bubbles.
• Vacuum bleed the system if you can. If that is not an option, bleed at least twice a day or so apart.

I used to buy the Cartel brand fluid when MOSS sold it. I don't think they carry Cartel anymore. The fluid in parts stores always looked different to me... cloudy and purple vs translucent purple with Cartel. The last fluid I bought from a vendor on eBay who was selling DOT-5 made for the military. It looks identical to and has been performing identical to the Cartel brand I bought for years. I like Cartel and the military fluid I bought off eBay.

You will get lots of people sharing their experience with DOT-5. Before those posts start let me caution you that most reported "failures" of DOT-5 have come about from people not replacing all the rubber in the system and/or not flushing the system. DOT-5 is compatible with all rubber compounds (EXCEPT Silicone) when the seals have not previously been exposed to DOT-3 or DOT-4. Again, there is no material incompatibility issue. That said, a lot of aftermarket brake parts I have purchased were not assembled with the famous red rubber grease but by having their seals dipped in brake fluid prior to cylinder assembly. Check what you buy. If the cylinders appear to be assembled with brake fluid as a lubricant, replace the seals even if they are new.

The other negative you will hear is that condensed moisture pools in DOT-5 systems. It probably could. However, putting in DOT-5 does NOT mean never replacing the fluid or keeping an eye on your braking system. Flush the fluid every few years just like you would with DOT-3/4 and you will not have issues.

 

[Rut]

Doug,
Thanks for your comments and I'm adhering to all of your statements since this is a virgin system. The MC was sleeved by Sierra and rebuilt by them as well and the calipers, wheel cylinders, and slave are all new/rebuilt, so no previous fluids in them. I like the screwdriver method of reducing the chance of bubbles and had planned on using a very large syringe with tubing on the end to do the same thing. I lost my power bleeder in the fire and will check with the local auto parts stores if they have loaners. The MGB has a remote bleeder on the clutch which helps a lot and the Bugeye will have one as well, routed back to the MC. I'm looking forward to this project and have high hopes since a leak will no longer ruin a new paint job.
Thnk, Rut

 

[dklawson]

Go for vacuum bleeders as opposed to pressure. With pressure you always stand a chance of forcing air into the fluid. Vacuum will actually cause any trapped bubbles to "grow" with the chance they will join and be drawn out of the system.

Firms that re-sleeve cylinders often recommend traditional fluid and/or refuse to warrant the repairs if you use DOT-5 fluid. The explanation I have always heard is that the restorations shops feel DOT-5 fluid does not do as good a job of lubricating the seals and therefore, the seals might wear out prematurely. I have no re-sleeved hydraulics so I cannot comment if that is a valid argument or not. However, using DOT-5 might invalidate your warranty so be sure to weigh that in your decision.

 

[Rut]

Doug,
Thanks again...advice will be taken on the vacuum bleeder. Sierra closed up shop a couple of years ago, so no warranty to worry about. I'll check all the seals and lubricate them with red grease before I fill the system just to make sure everything is as it should be.
Rut

 

[dklawson]

Remember that if the rebuilds were assembled using brake fluid for the seal lube, you should plan on replacing the seals with new even though they have never seen use. The red grease is supposed to be OK as is silicone grease.

 

[JPSmit]

I'm going to use Dot 5 silicone brake fluid in a new system and wondered if anyone has a brand they like? This will be in a Sierra sleeved Bugeye MC.
Thanks, Rut

Have been using it for years - and love it! However, I do find it is slipperier and can drip past the seals, so, I would suggest you not worry about brand, instead go to the store, shake all the containers and buy the "thickest." - the most viscous - you will hear a difference - In my case I think it was the generic stuff, but, others have had the same experience so it is not just me.

 

[Rut]

Thanks JP!
Rut

 

[nomad]

I first used it on my MGB in the 1970's when it first came out. The car was only a few years old and had major brake problems. A friend still has that car and I don't believe he has ever completely even bled the system. Hes just now starting to have issues. Dougs statement about the quality of the Dot 5 has me wondering since the fluid I have been using recently has given me problems. That 1970's was the clear purple stuff he mentions. Regardless, I love the stuff....no more rebuilding the system every few years. The issues I have read about it being compressible seems kind of ridiculous. Its a liquid, how compressible can it be? The issue with water pooling somewhere in the line hasn't caused a problem either though I suppose it could.

Kurt.

 

[glemon]

I agree with what Kurt said, I have been using the stuff on three cars now over 15 plus years, the only system leak problem I have had was the clutch master on my TR250, which I should have replaced instead of rebuilt.

Back when I used Dot 3 it seemed like replacing or rebuilding a slave or master cylinder was a regular occurrence, like once every year or two. Maybe it lubes better and so less wear? Also, no real bleeding or spongy brake issues for me.