Cylinder cup and dust seal


Hi All,

Am just having a look at my maitenance schedule from my workshop CD and am coming up to the time when I should change the master and wheel cylinder cup and dust seal. I've had a look in the diagrams of the master cylinder and the calipers but cannot find these parts labelled. Am sure it doesn't refer to the dust shield around the calipers and don't think it's reffering to any of the dust boots on the caliper hoses; can anyone shed some light, this is probably really obvious and appologese for lack of knowledge- help much needed and appreciated. Thanks for reading


What vehicle ?

Unfortunately people usually don't bother about this sort of stuff until something goes wrong.

The calliper dust seal boots are more likely the ones around the slave cylinders on the callipers.

Messing around in this area is normally fraught with problems, so I tend to leave things be until soemthing goes wrong. Funnily enough, I put new pads on the front callipers last weekend for the second time in my 4trak's life (110000 miles). To keep the crap out of the slave cylinder, I peeled back the flexible dust seal and stuffed in a good load of red rubber grease in the gap. This will at least keep the wet out until about 160000 miles. If the seal is perished or holed, then you will have to dig deeper and start risking getting grit into the slave cylinder and scoring it. Then the leaks will really start (and so will the one from your wallet ! )

Thanks, more info

Hi Rf Man,

Sorry, forgot the all important info; it's a Fourtrak also, a 99 Fieldman independent. I agree, suspect they meant the dust boots around the calipers but am still confused why they have described a master cylinder cup.... or any component on the master cylinder that will need changing as you say, especially as they recommend changing whatever it is on the master cylinder every two years.... very odd. Maybe I will leave this after all but I'm still intrigued, any thoughts gratefully received on this one. Thanks for getting back to me mate, sound advise.


Snap .... mine's a Fieldman too.

Hmmm .... sometimes I think that the manual specifies a service routine, assuming that the vehicle is being driven in the Australian outback all the time .... not necessarily a bad thing if you are Bundyrumandcoke.

Practically though, the sort of average use that a 'trak gets in the UK, farm tracks, shooting, plus quite a lot of ordinary road work, maybe towing a trailer, means that there isn't much dust and rubbish to contend with, especially if you keep the chassis clean with a pressure washer. I've found that under these conditions that the master cylinder and slave cylinders will last as well as any one on an ordinary car. At least the Daihatsu one can be taken apart and re-rubbered (unlike poxy Ford ones which are sealed for life, as my wallet knows !)

Thinking about the brake system in general, one of the best things you can do is to replace the fluid regularly. It washes out that nasty black crud that you find in systems that have never been touched (and which I think doesn't do the seals any good). It keeps the bleed nipples from seizing up, and it makes sure that there isn't any air in there. It's well worth investing in one of those automatic bleeders that work from the pressure of the spare tyre (reduce the pressure in the spare to about 5psi, or you'll possibly blow the reservoir off the master cylinder ! ) If you do get around to changing the fluid, whip out the bleed nipples and coat their threads with red rubber grease (it must be compatible with brake fluid, because it is designed to lubricate brake cylinder rubbers).

More exciting instalments to follow !

Respect to the Fieldman posse

Hi again RF Man,

Hate to sound like a rapper but it's good to hear from a fellow Independent owner..... Just a reply to say a worthy note again. Will try and get my mind into general service mode and not get too panicked by the CD manual; like you say Daihatsu have had to cover all the bases with wear and tear and I guess it made them money on the servicing of more regular cars anyhow. Thanks again, fluid soon to be changed.