Brake Fluid for TR3B

Castrol LMA is the most commonly used in british cars as this product will not affect the rubber parts. I do not recommend using dot 3. The only other product would be to use synthetic (I beleive this would be purple in color), however you would need to thoroughly clean out all lines and replace all rubber.

Let it be known, this is not official information, only my knowledge of the matter.

Thank you very much for your reply.  I was afraid that the system had to be thoroughly cleaned out to go to silicone ynthetic brake fluid.  I need to check color.  Thanks again.
teutontom@comcast.net

Good Day!

I'm sure our wiser techies can guide you but common sense says to have a clean system before changing to a silicone type fluid.  I used silicone in my car when I did the rebuild and it worked great. It bled easily and if my reservoir ever leaks my paint under the bonnet will remain safe. That alone is worth the price of admission.  Seems like anytime you see an older TR and check under the bonnet the paint under the reservoir is a mess.

I was told by  Mark Macy to let the silicone fluid sit for a week or so to make sure it had settled and all the air was out of the fluid. I followed what he said and everything worked out just fine.

Hope this helps out.

Cheers,

Ray

"Emily"
TR3-A
TS54473L

I apologize for the long post but perhaps this will help someone.  Tags 

"I was told by  Mark Macy to let the silicone fluid sit for a week or so to make sure it had settled and all the air was out of the fluid. I followed what he said and everything worked out just fine."

I just want to acknowledge what Mark told you and add my two cents.

During the restoration of Grey Lady, we suffered a huge set back with the braking system.  This was due mostly to the problems with the “Classic Gold” master cylinders, but also we had a small persistent leak at one caliper and problems with getting a rock solid pedal.  I have found in the case, as well as my TR250, that silicone hydraulic fluid  is a very different animal with some annoying characteristics.  

You will find that silicone fluid has a tendency to hold onto tiny, almost invisible bubbles of air.  So, since air is compressible, it thwarts a solid pedal.  So, what we resorted to bleeding the brakes in stages. 

·         We did an initial bleed in the morning, as an example, and then later in the afternoon or the following morning. 

·         We did not use the manual pump and hold technique.  We used a pressure-type bleeder and used minimal air pressure.

·         We raised the front of the car to help trapped air escape.

·         When pouring fluid into the reservoir, we were very careful not to agitate the fluid as this lessens the amount of bubbles that form.

As stated above, we had a persistent leak at one of the calipers.  This was an very, very slow leak, taking days and producing only enough fluid, adjacent to the caliper line fitting, to wet your finger a little when you probed the area. No drips or puddle under the car – just a little weeping.  This drove us nuts.  We did not want to leave it this way because to do so would be to give in and this restoration has been a “no holds barred” event so far. In addition, to ignore a braking system problem seemed kind of stupid.  In the final analysis, after trying “everything” that many experts and well wishing enthusiasts suggested, we resorted to a rather unique and radical decision.  This required a significant re-design of the seal between the line and the caliper.

Here is a copy of my post on the TR Register(UK) site.  Perhaps this information will be helpful to someone.

Posted  17 July 2011 - 12:06 PM

We are pulling our hair out over a very small BUT persistent leak at the front brake hose/caliper junction. The calipers are the later cast iron split-type and have been rebuilt by a well-known, reputable service company. Both cylinder seals are fine - dry as a bone under the dust boot. Fluid type is Dot 5. All other brake system components are new.

Under pressure test (brakes applied with temporary clamp on brake pedal, over 2 - 3 day period), a small drop appears every couple of days - enough to wet the end of your finger. Sounds minor, but of course this is unacceptable and would fail our MOT here.

So far, we have tried several sets of new hoses (TRW from TRF), and copper and aluminum crush washers. We even honed the surface of the crush washers using crocus cloth/plate glass, until both sides were perfectly flat. We have examined the "pad" on the calipers, using a 10x jeweler's loupe, where the hose/crush washer seats and both are free of scratches or other damage that might prevent the hose/crush washer to seal. Also tried a special Permatex aviation grade hydraulic sealant - no effect!

Any suggestions would be appreciated. Right now this is a game stopper!

We got many good suggestions, but frankly we had already tried all of them.  Read about the solution below:

Posted 07 September 2011 - 09:15 PM

SOLUTION FOUND - but it wasn't easy and I don't necessarily recommend it.

After trying everything in the book, including your kind recommendations and those of a few other TR friends, nothing seemed to work. We were up against the wall. It appears that the problem is in the calipers and perhaps has always been that way. The car was such a basket case when I found her, I wasn't even aware of the condition of the calipers. Even though there were completely rebuilt, the minute leak that hounded us was never detected until the car was close to being completely assembled.

 

The caliper bores were carefully measured. A special adapter was machined with the correct 45 degree cone tip, to match the 45 degree seat at the bottom of the bore. The material for these adapters is soft stainless steel tube stock and was so selected for its predictable crush characteristics. The principle is that we have added two additional metal to metal seals; one between the hose fitting at the top of the adapter, and one between the adapter and the bottom of the caliper bore.

This new arrangement was installed and carefully torqued. The system was then topped off with DOT 5 silicone fluid and pressure bled. Like we had done in the past, we let the system stand overnight to allow any trapped air to escape. The following morning the system was bled once again and an additional small amount of air was removed. We tested the pedal and it felt very firm. At this point, a Friday, we rigged up a stick to apply constant pressure to the brake pedal.

Monday morning we checked the connections at each caliper and found no leaks. So far, so good and following a brief test drive everything seems to be OK.

I sure hope this is a permanent solution. If I ever have to disconnect the calipers, new adapters, hoses and crush washers would be required. If this ever happened, I would probably replace the calipers.

Thanks Ray.  Appreciate your comments.  I just checked the brake fluid and found it was very clear, not purple or synthetic.  Car is going into storage for winter here soon, so I will wait til next spring to change to synthetic as you did with your rebuild. 
teutontom@comcast.net

Good Day!

Glad I could be of some assistance. We also used a brake bleeding system we purchased from Moss Motors that ran off pressure from a spare tire with the tube attached to a special cap on the master cylinder. This worked GREAT. We did all four wheels along with the clutch slave cylinder in under 20 minutes and that was 3 years ago. We haven't had to touch it since. Solid pedal and we couldn't be happier. I will add that even though we did not have to replace wheel cylinders we did install  new stainless steel brake lines which I'm sure helped.

Tags went into great detail with some very good information. This is one of the many benefits of belonging to TRA. Regardless of where you live you are never alone with your challenges. Someone is always out there to help.

Cheers,

Ray

"Emily"
TR3-A
TS54473L

Ray - Great Information and I can't thank you enough.  I will use it this winter when working on my car for the spring.  I have made copies for my files as well.  THANKS!!!
teutontom@comcast.net

Thanks again Ray.  Great info that I will use to better my car.
Teutontom
1962TR3B TSF179L