Silicone brake fluid

[Marty too]

I tried to resurrect a thread from 2006 but couldn’t because of a time period but I have a question(s) and/or am looking for some honest opinions about the us of “Silicone (type 5) brake fluid.” Please note, I did a Google on silicone brake fluid and while there were five positive and five negative comments on this stuff, no where have I found it to be said “do not use type 5 in lieu of type 3 or 4 because-------.” So my question is------why not totally flush out the type 3 or 4 that is in the Workhorse brake system and replace it with type 5? (and don’t tell me because the manufacture said to use type 3 or 4. They’ll use the cheapest stuff available.) Anyway, this would or should eliminate the moisture problem that seems to be the culprit in all the Workhorse brake problem. I noted that Driver had quite an informative post in 2006 on the subject of brake fluid but it covers mostly the type 3 or 4 fluid. His one negative I found was in the price for type 5 which a close friend, whose been using it for over 10 years in his vehicles and heavy equipment also said this was a draw back.

Any honest thoughts on this subject:?

Marty

[DriVer]

Quote:

Originally Posted by Marty too Any honest thoughts on this subject:?

Marty, I'm going to try to abide by your guidelines and give you the best asnwer that I have.

If you are out of warranty, and if you are going to want to flush and use DOT 5 Silicone Brake fluid in your Workhorse, that's all up to you.

If you (anyone) is in warranty, quite simply you will void your warranty.

If any action is pending in regard toward having the 50901-C Brake Campaign completed on your vehilce, having DOT5 installed may exclude you from the campaign however that said ... it's only my opinion.

According to the Workhorse Chassis Guide (Official Publication)

CAUTION:
Do not add DOT 5 brake fluid to the master cylinder reservoir. DOT 5 fluid is silicon base whereas the correct DOT 3 fluid is Glycol based. The two will not mix and the DOT 5 fluid can cause major damage to the anti-lock brake module and other brake components.

There you go! I hope this answers your question.

[mfire1339]

Marty too,

I have a bottle of dot-5 fluid before me and it says ( DO NOT USE ) on anti-lock braking systems.

Mike Fire

[oemtech]

Marty,

If you have a racing version RV then I think DOT-5 is the way to go. But, me I use plain old Dot-3 or 4 which ever is on sale as I change my fluid yearly for about $12.

Considering the cost to flush the system ($$$), DOT-5 runs a about $12 (3x=$36) and you run the risk of some $5/tech will top off your brake fluid with DOT-3 and totally hose your brake system its not worth it.

[Toolslinger9]

I don't really believe the problem can be solved by different brake fluid. The problem is that the pistons get warm and warp. When they warp, they stick or drag and do not release. I put in rebuilt calipers after my brakes failed and standard brake fluid. 10,000 miles later, all is well.

[Marty too]

Driver: Thanks for your honest opinion, that's what I look for. Never gave thought that I might get "tossed under the bus" on the recall should I use Silicone. Also, I am well aware that Silicone and Dot 3 or 4 can NOT be mixed.

Mike: I've seen that caution about Silicone can not be used in anti-lock brake system. My thoughts are------WHY NOT?? I have not seen or found a valid discription as to "Why Not." If you know, I'd like to be educated on this theme.

oemtec: I woudn't mind twice the price you posted if it gave me a sense of security while out on the road. Also as you pointed out, I wouldn't let a $5 tech get near the master cylinder with out specific instructions or I'm standing over him with a club even if I had to furnish the fluid to top off the master cylinder.

Toolslinger: You have an interesting point about warping. Everything I've read or seen has been swelling which is a bit different. Never a thought about warping.

To each and everyone of you guys that took the time to post your thoughts, I do thank you. It's what makes this forum worth while.

Marty

[mfire1339]

Marty,


DOT 5 is NOT recommended for any vehicle with ABS brakes because it tends to aerate when cycled rapidly through small orifices. From the manufacturer web site. That was easy.
AGS Co.

Mike Fire

[mrschwarz]

Having worked in the brake parts manufacturing industry many years ago, we sold DOT 5. Here are some of the features and disadvantages I remember:

1. It is not hygroscopic. It doesn't attract or absorb moisture. This can be both good and bad. If you store a vehicle for a long period of time with driving it, DOT 3 and 4 brake fluid can absorb moisture through the hoses and rubber seals. If you leave a container open on a workbench, it will absorb moisture. DOT 5 doesn't do this.

The US Army performed a test of silicone brake fluid in Panama and Alaska. They converted some vehicles to DOT 5 and parked them. They also had DOT 3 vehicles parked. All vehicles had new hydraulic parts installed before the test began. If I remember it correctly, they sat for 3 years. At end of the test, they tore down all the brakes. In the case of the DOT 5 vehicles, they brake systems looked like they did the day the test began. In Alaska, there was some rust and pitting in the DOT 3 vehicles, but the brakes worked. In Panama, the brakes in the DOT 3 vehicles were rusted so badly that the pistons fused in the bores, The cylinders needed to be replaced.

The disadvantage of this property is that if there is any moisture in the brake system, it will not be absorbed by the brake fluid. It will have a boiling point of 212° and can cause vapor lock.

2. Silicone fluid is compressible. Actually, all fluids are compressible to a degree. Silicone is much more compressible than glycol-based (DOT 3 or 4). This results in a brake pedal feel that is softer.

3. As was already mentioned, silicone tends to aerate when agitated. That is why it's not recommended for ABS.

4. DOT3 and 4 brake fluid is an effective paint remover. Spill some on the fender of a car and see what happens. Silicone doesn't do this.

[John350]

I used silicone brake fluid in an non abs corvette used for racing. Due to the viscosity increase compared to dot 3 or 4, it was difficult to bleed. When I poured it in the master cylinder, it had a tendensity to aerate. If I held a shop light to the reservoir, the fluid was not clear. I condluded that was air entrained in the fluid. Leaving it set overnight, the fluid would be clear. also, using a heat lamp on the reservoir cured the problem. I eventurlly switched back to a glycol based brake fluid.

I have 26,000 miles on my 2003 w22 chassis and not had a known brake problem. I flushed my fluid this year, first time and the rears came out black. Thanks to this forum, I am aware of additional suggested maintence items.

Happy Motoring
John
2003 Tiffin Allegro Bay
W22 Chassis 8.1L

[DriVer]

Quote:

Originally Posted by mrschwarz The US Army performed a test of silicone brake fluid in Panama and Alaska. They converted some vehicles to DOT 5 and parked them. They also had DOT 3 vehicles parked. All vehicles had new hydraulic parts installed before the test began. If I remember it correctly, they sat for 3 years. At end of the test, they tore down all the brakes. In the case of the DOT 5 vehicles, they brake systems looked like they did the day the test began. In Alaska, there was some rust and pitting in the DOT 3 vehicles, but the brakes worked. In Panama, the brakes in the DOT 3 vehicles were rusted so badly that the pistons fused in the bores, The cylinders needed to be replaced..

mrschwartz, Thank you for posting this. The results of this research validate one of the issues that I have been trying to bring into to focus here on the board. For all those efforts, select people continue to discredit anything in regard to fluid and they are so intransigent about placing fluid as one the the prime ingredients that contribute to the failure of the calipers.

People that examine and analyze failures and disasters in all cases have reported that several cascading events must occur in order for something to catastrophically fail.

What this study revealed is that over time hygroscopic brake fluid will do its job and unless owners find a way to renew the fluid and purge it of moisture, brake caliper piston/bore relationships will continue to be compromised. This will unfortunately remain true even on completion of the 90501-C Bosch Caliper Campaign.

Once the campaign is complete and the brakes are repaired failing to do ones part in providing good service may only invite this situation to occur again.

I will continue to suggest that if an owner from the start of their new vehicle ownership routinely flushes their brake fluid (1 to 2 years) that the service itself will remove one of the triggers that could contribute toward a caliper seizure failure.

[tropical36]

A lot of details here from other members, so I'm just going to say....DON'T DO IT....and if you were to, then only on a new system that never had any fluid in it to start with.
If you want to raise the boiling point more than what it is now, then replace what you have with DOT 5.1 which is completely compatible with DOT 3 and 4. After that, change it out every 3 to 5 years, which is more hydraulic brake insurance than 95% of all vehicles on the planet.

[DriVer]

Quote:

Originally Posted by tropical36 After that, change it out every 3 to 5 years, which is more hydraulic brake insurance than 95% of all vehicles on the planet.

The majority of owners here that post in regard to change interval seem to want to change their fluid ranging from 1 to 2 years. Fluid is inexpensive compared to the thousands one might spend on repairs.

[tropical36]

Quote:

Originally Posted by DriVer The majority of owners here that post in regard to change interval seem to want to change their fluid ranging from 1 to 2 years. Fluid is inexpensive compared to the thousands one might spend on repairs.

Yes, I'm sure that sooner is better than later, but how many are going to do that? Most are lucky to change it at all and it's not the fluid that gets expensive, it's that most won't be doing this themselves and prices to do the job fluctuate all over the place.

[DriVer]

Quote:

Originally Posted by tropical36 Yes, I'm sure that sooner is better than later, but how many are going to do that? Most are lucky to change it at all and it's not the fluid that gets expensive, it's that most won't be doing this themselves and prices to do the job fluctuate all over the place.

tropical36, Then what we're talking about then is a challenge to all owners to make sure they consider doing this service sooner than later. The 2009 Workhorse Chassis Guide recommends 2 years. Oemtech recommends every year.

Personally, I can change my brake fluid using Speed Bleeders so my cost is only associated with the fluid.

The average owner can expect an hours worth of labor "or less" and the cost of the fluid if they go have the service accomplished.