Brake fluid

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XTIGERX

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I was changing out hydraulic fluids this weekend. Rebuilt the rear wheel cylinders and used up the last of a fairly new container of Castrol.

Had to buy more for the clutch. I went to 2 Pep Boys, 2 Autozones, a Kragens and an O'Rielys and none carry Castrol brake fluid. Is it not available anymore? Is using other than Castrol still a problem with the seals? I have no booster.

I grabbed a container of Gunk clutch fluid thinking there wouldn't be as much of a problem with it in the clutch system since I'm rebuilding the master. It seems I have to re-build the master every other year. The master was new and is only a few years old. Is this the norm? Or am I missing something?

Any suggestions?

Thanks, Justin
 
The brake fluid question does come up from time to time and the general consensus seems to be any DOT 3 or 4 name brand fluid will be fine, just stay away from silicone fluid. I have been using Valvoline synthetic Dot 3 &4 in recent years, with no problems. Do not confuse this synthetic with silicone! It was recommended to me by a successful autocrosser. Supposedly, the more recent rebuild kits have better rubber than what used to be available. If your car tends to sit for an extended period, itdoes not hurt to flush the hydraulics with new fluid yearly as preventative maintenance.

As for rebuilding, I do not think you should have to be doing it that often. Is the rubber just leaking fluid after a time? Are you breaking the cylinder bore glaze before replacing the rubber? That can be done with fine grade emery cloth wrapped around a wooded dowel of appropriate diameter. Do it gently! Just enough pressure to rough up the glaze ever so slightly. And flush vigerously and wipe down thoroughly to eliminate any loose grit. Don't use sand paper, the grit does not break down like emery cloth grit. You do not want any thing embeded in that soft aluminum. Of course you can also have the bore resleeved with brass and not have to be so careful!

Cheers, Gene
 
Silicone brake fluid

If you are doing a total rebuild of all brakes and master cyclinders can you then use the Dot 5 Silicone fluids? Seems the way to go if you don't drive the car alot, escpecially since they don't absorb moisture. My understanding is that the problem is when you have existing Dot 3/4 in the system and mix with the Dot5. Considering what everyone here says I know a lot of guys using the Dot 5 and loving it:confused:
 
Agreement

Concuring with other comments, my experience with re-building customers' brakes shows that a complete flush and all new seals provide the environment for using DOT 5 (high end) products. If you leave any other fluids in the system or a few of the older seals, some nasty chemistry can occur (not always) and you will see things turning black as the seals break down. This problem has haunted many of our servo re-builds as impatient owners bolt the nice clean servo into a contaminated system. DO NOT MIX FLUIDS !!
 
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