cleaning up brake system

[dansalisbury72]

As soon as my parts arrive I am going to start work on getting my brake system put back together. This may be a dumb question, but is it wise to flush the brake lines with anything other than the new fluid? Is there anything I can run through the brake lines to 'clean' them?

thanks...

Dan in NC

[4flattires]

Flush? Yes, emphatically. With brake fluid.

No real reason to run a cleaning agent through the pipes, unless you have some serious rust going on, then I would replace lines (safety issue).

Brake fluid is hygroscopic, meaning is absorbs water. Always use new fluid, and keep the canister well sealed. Introducing another fluid is asking for trouble with its possible reaction to other rubber parts.

Jeff

[thixon]

Jeff is right on. The only thing I'd introduce into my lines other than brake fluid is compressed air.

If the lines are in good condition, then just start running fluid through the system. Get or make an easy bleed to make this job less of a PITA.

If the lines are corroded, then replace them. You can source the line locally, and use your old fittings. Remember, don't use fittings from the auto parts store. Brit fittings are different (do a web search for more info). And if you already knew all this, then forgive me for wasting your time!

[xsbowes]

The only thing I'd introduce into my lines other than brake fluid is compressed air.

Be careful with the compressed air, your compressor can build up moisture inside and blow that condensation right into your brake line, unless you have some sort of moisture separator or air dryer.

[thixon]

Be careful with the compressed air, your compressor can build up moisture inside and blow that condensation right into your brake line, unless you have some sort of moisture separator or air dryer.

Agreed. Sometimes I assume that because I'm aware of something, everyone else is as well.

[Jeff Aronson]

Flushing out the old fluid with new fluid will likely improve your brake operation, too. It's amazing how much moisture old brake systems absorb over the decades.

Over this past year I've had to replace the rear brake lines on one of my II-A's. I've ordered the brake lines from Rovers North, unrolled them c-a-r-e-f-u-l-l-y so as not to kink anything, and found the length perfect for every application. The fittings also screw right in.

If you have to replace lines, I'd recommend doing it the easier way.

Good luck,

Jeff

[SafeAirOne]

... It's amazing how much moisture old brake systems absorb over the decades...

I've asked this elsewhere with no difinitive answer, but if one is flushing/replacing all the rubber in the brake system (no mixing of old and new fluids), can one use DOT 5 silicone brake fluid without dire consequences?

The DOT 5 fluid will NEVER absorb moisture.

[jac04]

^^ I'm sure you will get a lot of people to comment on the silicone brake fluid topic, but I would not use it in a Rover. The rubber in the british brake components seems to be sensitive to what fluid you use - that's why you always hear to use the Castrol GTLMA fluid. On my Rover restorations, I have always used the GTLMA fluid and then changed the fluid on a yearly basis. By the way, on my 68 Camaro restoration I used silicone fluid without any problems so far.

Now, not absorbing moisture seems like a good thing, but if any moisture gets into the system it will tend to collect in one spot - not sure of the consequences of this.

[Leslie]

If you are replacing all the rubber bits, yes, you can convert to a DOT5. However, if your vehicle's been using LMA for decades and you just drain and refill w/, then yup, the rubber's going to fail. W/o changing everything out, stick with LMA, either Lucas or Castrol.

I know DOT5 would be 'better', but, I didn't change out 'everything'.... so I am continuing to stick with LMA (it does surpass DOT3 and DOT4 specs). I order Castrol GT/LMA by the case at a local parts store (which, I find interesting, that the bottle has recently changed and now says 'synthetic', and also is made by BP in Germany). Last case I bought, came out to be about 2.50 for each 12oz bottle. (FWIW, I prefer buying the case of small bottles, so that I can open a new bottle when needed, w/o wasting a lot if I don't have to use the whole bottle...).

[thixon]

Leslie,

I know you know this, but some may not. The issue is the old natural VS. synthetic rubber bits, and how each reacts to brake fluid.

The big complaint I have against the DOT 5 silicone is that its viscous, and is a plain b(tch to bleed if you have air in the system (or can be anyway). Its also more compressable than LMA. In addition, if you have natual rubber bits, DOT 5 Silicone will make them swell. Another reason not to use it in your rover. The only benefit (to me personally) is the nonhygroscopicity (gees, is that a word?)

On the plus side, silicone will not remove paint if spilled.

[yorker]

I've used silicone since 1997 with a mixture of new and old bits and have never had any problem with any seals or hoses. It seems to be one of those things that some people can get away with and others can't. I do know at the time I did experiment with the fluid and soaked various used seals in the silicone to see what would happen- somewhere I still have the jar with the seals in it- nothing spectacular happened.

[thixon]

I did experiment with the fluid and soaked various used seals in the silicone to see what would happen- somewhere I still have the jar with the seals in it- nothing spectacular happened.

Figures. Its billed as being compatible with other fluids anyway (I assume it has to be to qualify as DOT approved.)

[Tim Smith]

It seems to be one of those things that some people can get away with and others can't.I did not. Well nothing terrible happened but on my SIIA with the common reservoir, the clutch peddle slowed down too much to double clutch properly.

Silicone did seem to be a thicker fluid all together so either my rubber seals were swelling or the fluid was too think to flow quickly. Not sure what it was.

I'm sticking to Castrol GT/LMA going forward. Much cheaper any way. :thumb-up:

[yorker]

I guess it can be expensive but I really have not gone through that much Silicone brake fluid, I'd still have most of the first gallon I bought if I hadn't spilled it all. I replaced it with a gallon I bought for $25 at a local surplus store, it isn't like you end up using a lot of it. Maybe a bit to flush out the system once in a while or if you change flex lines.

But like I said different people have had different results. YMMV