Brake assy lubricant compatible with Silicon Brake fluid

[Craig Allardyce]

Yes Malcolm - I'm sorry Matty - I have stolen your post here.............

I fitted silicon when I did the mod in '82 - it's been in there ever since - no signs of cylinder wear anywhere in either the brake or clutch systems - just a few little issues you need to be aware of - don't.
It costs an arm and a leg, is not recommended by anyone in the trade and cannot be mixed with any other type of fluid........ good points - no corrosion, and can pour it over your car without one jot of damage.............
Dow Corning used to supply it to limited outlets - then stopped abruptly - I then found Shell marketed it for a short time under their "Ultra" brand - then stopped - fortunately, Harley Davidson use it and it can be purchased from motocycle shops - WARNING, WARNING, WARNING.........!!!!!
If you consider doing this - you must competely drain, clean and flush your entire system - and MUST REPLACE every rubber in the system - if you don't replace the rubbers they will turn to MARSHMALLOW when this stuff makes contact with those which have come in contact with "normal" brake fluid -

End of the day - would I do it again - NO - but I'd flush and change the entire system twice a year - after winter and summer.

Cost per 330 ml = $32

frats,
Rosco
ps yes it's purple - but after 12 months or so without a drain off - goes opaque grey/green............

Hi Rosco,
I'm just wondering what you used as an assembly lubricant for your brake parts when using silicon brake fluid.
I'm going down the path of using silicone brake fluid and have/am replacing all my brake components for new/rebuilt items including all pipe and hose work. I have done a fair amount of research and have found that GRR rubber grease is not compatible for use with DOT 5 fluids. I looked at using DowCorning Molykote 55M silicon Oring grease, but this stuff by design swells Orings for better sealing which would not be good for Wheel cylinder cups. It also isnt compatible with SBR type rubbers.
I have had all my cylinders SS sleeved and have had bronze pistons made up.

DSC00432.JPG (195.57 KiB) Viewed 1299 times

My two motivations for going this way is I'm trying to prevent the pistons for corroding and seizing as the originals did (alloy and steel), and I dont want the drama of any possible leaks ruining paintwork, as would be the case if I used normal brake fluid.
My next question is to the brake cup manufacturers to find out what composition they are made up of, SBR, EP, Neoprene, etc. Most over the counter sales persons at ABS and alike just give me a stupid look when I ask.
Fluid wise I will be using this stuff. http://www.ebay.com.au/itm/BRAKE-FLUID- ... 2a24c5682d
It seems to tick all the boxes as far as compatibility and the fact that they state that it exceeds the FMVSS 116 specification.
Cheers.
Craig

[Trev]

Something I just came across, hope it helps, I haven't read it yet .

http://www.roddingroundtable.com/tech/a ... fluid.html

[Craig Allardyce]

Thanks Trev,

that article is more about the fluids and pro's/cons of normal fluid and silicon based fluid.
I'm trying to find a suitable assembly lubricant to coat my wheel cylinder pistons and cups that is compatible with silicon brake fluid.

I appreciate the reply.

[Marty K Bird]

How much did it cost to get each wheel cylinder done?

I pulled my four off today and need to have them sleeved aswell.

[Craig Allardyce]

How much did it cost to get each wheel cylinder done?

I pulled my four off today and need to have them sleeved aswell.

They cost me about $60 ea which included new cups. This was cheaper than buying new cylinders which average around $80 ea.
The bronze pistons were an extra cost to get made up.

[Marty K Bird]

Thanks for the reply, someone put me onto a place in silverwater that does them for about the same price, sending them off tomorrow hopefully

[rosco]

Hi Craig,
sorry for taking so long to reply to you - I've been off the air (again) for some time and am just picking up matters as best I can.

I did not use any pre-assembly lube for my installation. I simply wiped some Dot 5 onto eveything which I had dismantled.
Anything which was new was disassembled and wiped clean then dipped/wiped with Dot 5 and assembled - I have not had one issue with using this fluid.... apart from the expense AND the necessity to care spare fluid at all times.... you CAN NOT mix normal brake fluid with this stuff, it will destroy all rubbers very quickly and render your braking/clutch system inoperative.

As for purchasing the fluid, I initially bought Dow Corning when I decided to change - then it was no longer available - then Penrite supplied it - and again they stopped retailing it.... fortunately, and you should remember this - Harley Davidson use it on some of their motorcycles and it will need to be in supply for many long years... but, at a cost....

I like the cheap $88 per litre plus freight of the link you posted.... I might just have to get a litre in as reserve... from memory, the last time I purchased the H/D stuff - when our club went to Tassie, it was around the $35'ish for 330 ml....... and is probably now much more expensive..

It is certainly worth the effort if you can discipline yourself to keep the systems quarantined from normal fluid - it lends itself extremely well to classic vehicles which are seldom used - and the re-assurance that any spills (we don't have those anymore, do we?) won't strip you expensive paint.

I have replaced the rear cups in one of my rear wheel cylinders - there wasn't one jot of a sign that the cylinders or pistons had worn - the only reason I replaced the cups was that I had damaged one (minisculey) and had the replacement packet handy.... the only sign I could see of any wear was a dulling of the working surface of the cups - nothing else anywhere.

The fluid will change colour from that when new - it tends to go a duller less luminous colour - but works perfectly.

I have not had issue with any fading - this was one of the "no-no's" we were warned about when the new fluid came onto the market.... yes, it might fade if you were running around Bathurst and braking 2 plus tonnes from extreme speeds at the last possible moment.... but for our purposes, I can't see an issue....
I have towed boats and caravans with my old bus with silicone fluid - and have not noted any change in the "normal" rate of brake fade down long and steep/winding grades.....

The big down side is the expense and need to keep the fluid completely quarantined..... apart from that, I fully expect you will become an advocate for the stuff....

I did make the most offending mistake when I put my old bus together thirty years ago with the disc braked front end etc. etc..... I fitted a used Girling booster - and, no matter how many times I flushed the unit out - it killed the valves and caused the system to malfunction in a matter of days.... thence to the PBR VH 40-L - and I haven't looked back...

frats,
Rosco

[Craig Allardyce]

Hi Rosco,

Thanks for the reply and no worries about how long it took. Everyone's busy these days, no exceptions here that's for sure

Cheers