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Darren S

Well Known Member
On the first flight of the day the left brake pedal depresses quite a bit. When I release the pedal and then step on it again, it is much firmer. The right pedal doesn't do this so something is leaking somewhere.

I didn't build the plane so I'm looking for a little guidance before I hit the hanger tomorrow.

Is regular automotive brake fluid usually used ?
I suspect the left caliper. I think I'll look there first rather than the brake reservoir.

Thanks,

Darren
 
If you can ask the old owner what fluid he used. Most aircraft do not use car brake fluid because it will harm paint, and absorb moisture. It would not be a good idea to mix them.

You will need to bleed the brakes from the bottom up using a pressurized system of some kind. (see link below) I made one using a 1 gallon garden sprayer filled will the red Mil Spec 5606. This of course is a subject of hot debate.

Brake Fluid Wars --------------> http://www.vansairforce.com/community/showthread.php?t=68104&highlight=5606

Brake Bleeder ------------------>http://www.aircraftspruce.com/catalog/lgpages/hydraulicBleedertank.php
 
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Thanks for the help.

Bleeding the brakes is a two man job. I will try to find out what the previous owner used. If not I may have to drain out all of the fluid and start over.......... sheesh........I think I may wait till the annual in May since there isn't really a safety issue.

Darren
 
Is it a Matco master cylinder unit? After you bleed the brakes, if the problem recurs you may need to use an overhaul kit to make sure the O-rings are okay (available from Van's). if that doesn't solve the problem then consider an alternative such as the Grove units. I switched years ago after having a similar experience, and have had no problems since.

Chris
 
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