Brake Lines And Fluids

[Pumpkin]

A tip from the British Auto Works in North Plains OR. www.britishautoworks.com

Notes.
A central theme to this service tip centers on brakes. This one is no different..in hard capitol letters.

DON'T USE ANY TYPE OF SILICONE BRAKE FLUIDS IN YOUR BRAKES OR CLUTCH SYSTEM!!

Some LBC owners have indicated they have benefits of these new fluids. BUT not in your brakes or clutches. They are good products but not hydraluic fluid.

The biggest issue is that the seals and hoses used in the system react to the synthetic fluid, and begin to fall apart very quickly. If you have these fluids in your system now, you will need to flush it out as soon as possible. And replace all your rubber lines and seals . Then use only a DOT 5 or DOT 3 fluid. They reccomend Castrol as the best.
chuck

 

[skywords]

Chuck I think you meant use only Dot 3 or 4 not Dot 5(silicone)?

 

[Pumpkin]

Brake fluids

Chuck I think you meant use only Dot 3 or 4 not Dot 5(silicone)?

No I didn't mean to say that.. What, I missed was the comment,, "Castrol" is the only company that is listed as a non-silicone /non-synthetic DOT 5 product. Lockheed makes a DOT 5 under another name... And IS a silicone product..

So the DOT 3-4 and the Castrol 5 is good..

I do apologise to all for this mis-understatement


Chuck

 

[Tom H]

I put silicone fluid (General Electric brand) in my brakes and clutch systems in 1988 and have not had any problems since. Silicone fluid seems to absorb much less moisture. Prior to this I always had my brakes gum up with yellow gunk as the fluid absobed moisture here in high humidity north east Ohio. And the silicone has caused absolutely no degradation or deterioration of any seals.

Tom H

 

[panjang]

Confusingly enough, Dot 5 is silicone based, and Dot 5.1 is non silicone (glycol) based. Not everyone, including many retailers, seems to know this.

The main objections to silicone based fluid seem to be:-

A) All traces of old fluid have to be removed, all seals should be replaced, and the system meticulously cleaned before silicone fluid is used.

B) it is slightly more compressible than "traditional" fluids, and gives a spongier feel to the pedal.

C) Because it does not absorb water, supposedly its main advantage, any water which condenses within the system stays in droplets, causes corrosion, and is difficult to remove, as it is at the bottom and bleed screws are at the top of cylinders.

Thus, it is said by some, it is better for any moisture to be absorbed by the fluid, so that it does not cause corrosion and can easily be removed by regularly replacing the fluid.

I understand that, because they are hygroscopic, traditional fluids absorb moisture not only via the surface of the fluid in the reservoir, but via the cylinder seal edges, and by osmosis through micropores in the seals and the walls of rubber based hoses.

As silicone fluid does not attract water so readily, I think probably the only source of moisture would be condensation on the reservoir walls from the air above the fluid in the reservoir. If this is really an issue, this air could easily be kept dry by incorporating a silica gel cartridge into the filler cap. If the silica gel were in a transparent cartidge and had a color indicator it could be easily changed when necessary.

Stainless steel braided Teflon hose would probably avoid the possibility, if any, of moisture entering by this route, but there are other objections to these hoses, including fatigue cracking, this or physical damage being hidden by the braid, many do not have DOT approval, raising insurance issues, the DOT expected lifetime is only 5 years, and concerns about its use in cold environment leading to a higher risk of fatigue cracking.

I have considered changing to silicone for the NSU at least, which is rarely used, but can't face stripping down all those bits yet again, especially the twin caliper inboard front disc assemblies, so I renew the fluid every 2 years by pushing a litre of new fluid through via the reservoir to each bleed point in turn.

 

[Gary M]

Dot 4 fluid

As I recall DOT 3 will also ruin natural rubber seals as used in british cars. Use DOT 4 which is safe for natural rubber. I solved the water absorbtion issue in my first alpine series V by getting a rubber bellows cap liner from an american brake master cylinder and cutting it down to fit the resevoir.

 

[RootesRooter]

Another problem I've heard of with using silicon brake fluid in our cars is that the brake light switch often goes kaput soon after.

 

[Chazbeam]

do not use synthetics with standard

OK so i grabbed a bottle of dot 3 high temp synthetic off the auto store shelf without really giving it a good look over, i was in a hurry and didn't spend the time to pay attention..Also i thought dot 3 was dot 3! one would think they would DOT it a different freeking number..(yeah yeah it does not work like that)..,SO
I topped off my brake and clutch and a few days latter they are leaking like sives right into the interior of the car all over the floor and loosing fluid by the time i have drive about 30 mill.. and its both cylinders and some of the leakage looks like the color of rubber... I could not be more pissed at myself over it and being careless but i post this as a lesson to everyone that may make the mistake, DON'T!
Not all brake fluid is created equal..... what does not kill me makes me learn.. its just painful lessons...


Cheers

 

[pcmenten]

Ach, my head is hurting.

I made the mistake of using silicone brake fluid in my MGB and had to rebuild the master cylinder. It's interesting to find out that's the reason why my brake light switch failed.

So, here's the question; what do we recommend?

I picked up some steel braided hoses, with adapters to adapt Mustang II calipers to the Sunbeam plumbing. Now I think I'll completely re-engineer my brake system. Mustang II calipers, compatible flexible hoses (non steel braided. I never liked them anyway) without the use of adapters, and compatible fittings to fit up to a new steel line in the front. I have the F10 master cylinder. This gypsy lash-up will be a scary ugly combination of Metric and SAE fittings.

 

[260Alpine]

Paul, I use Valvoline Synthetic DOT4 in everything. Never a problem.

 

[Gumby]

I realize that this thread is pretty old. However, back in my day, 1976 when I owned my first LBC, a 65 Series IV Alpine, I learned through the local British car community, and from a man named Jan at Sports & Imports (Sunbeam Dealer at one time) in Tacoma Washington, that the ONLY brake fluid to be used, per the manufacturer was Castrol GT-LMA fluid. This was verified through the Jaguar dealer with my dad's 64 XKE. Again only the Castrol GT-LMA fluids were to be used.

There is something different about the fluids, and the LMA stands for Low Moisture Absorption. In my original Alpine, my 65 Imp, my dad's Jag, my brother's MGB, and every one of the Triumph, Norton, and BSA motorcycles I worked on over the years, the only brake fluid I used was the Castrol GT-LMA. It got harder and harder to find over the years, but it's still available. For my latest Sunbeam (Pictured to the left), the brake and clutch hydraulic overhaul ( caliper strip and rebuild (or brand new depending on what I find on the inside), new wheel cylinders and new master cylinders, new flex hoses, and new steel lines...they are 57 years old now), all will be done with this same fluid only. Simply put, why take a chance? I only want to do this once. Knowing the entire brake system is new and factory fresh, will give me a lot less stress the first time some Jack Hole pulls out in front of me.

 

[loose_electron]

This gypsy lash-up will be a scary ugly combination of Metric and SAE fittings.

So will you use metric or SAE brake fluid?