Van's Air Force
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brake cal. puck machining
- Thread starter dent
- Start date
Better fluid?
Can a Higher Dot Brake fluid be used?
I ran Motul 660 Brake fluid in my race car its dot 6 and has an extremely high boiling point and i never had any fade. flushed every other month due to being in a vented master cyl. It is hydroscopic and absorbs water in the atmosphere quite quickly so flushes are required more often. It won't be as bad in a sealed system like mountain bikes, some motorcycles and I'm not sure but our RV's A water brake fluid tester be used to check the change interval. I would flush @ Annual regardless.
My 2 Cents.
Good luck
Can a Higher Dot Brake fluid be used?
I ran Motul 660 Brake fluid in my race car its dot 6 and has an extremely high boiling point and i never had any fade. flushed every other month due to being in a vented master cyl. It is hydroscopic and absorbs water in the atmosphere quite quickly so flushes are required more often. It won't be as bad in a sealed system like mountain bikes, some motorcycles and I'm not sure but our RV's A water brake fluid tester be used to check the change interval. I would flush @ Annual regardless.
My 2 Cents.
Good luck
az_gila
Well Known Member
Lots of discussion on that topic here -
http://www.vansairforce.com/community/showthread.php?t=16685&highlight=dot5+fluid
What you are proposing would only reduce the heat transfer from one of the two brake pads. The one on the outboard side of the caliper would still have full conduction into the caliper body. Even the piston side would have some through via its contact with the guide pins.
Regardless, in my opinion it is a search for a solution to a problem that doesn't exist. And I believe that is why you are search for a way to do a modification that none of the brake manufacturers have bothered to pursue
RV's do not operate like race cars. We do not execute a max performance stop every 10 to 20 seconds. Even flying close patterns while practicing short field landings to a full stop I see no noticeable degradation in my braking performance. There of course has to be some, because brake performance is based on how much heat the braking system can absorb... If it is already holding some heat above ambient, then absorption capacity is reduced, but it causes a small enough change that it is difficult to detect.
Regardless, in my opinion it is a search for a solution to a problem that doesn't exist. And I believe that is why you are search for a way to do a modification that none of the brake manufacturers have bothered to pursue
RV's do not operate like race cars. We do not execute a max performance stop every 10 to 20 seconds. Even flying close patterns while practicing short field landings to a full stop I see no noticeable degradation in my braking performance. There of course has to be some, because brake performance is based on how much heat the braking system can absorb... If it is already holding some heat above ambient, then absorption capacity is reduced, but it causes a small enough change that it is difficult to detect.
Like Scott says, this should never be a problem with RV brakes.
If you have to do a hard stop on landing, it should be for a very short duration.
If your brakes get hot while taxiing, you are taxiing much too fast. And if you are taxiing that fast, you should have enough rudder authority to turn.
If you have to do a hard stop on landing, it should be for a very short duration.
If your brakes get hot while taxiing, you are taxiing much too fast. And if you are taxiing that fast, you should have enough rudder authority to turn.
Some of the Clevelands on the twins etc. already have such a piston. I've replaced quite a few of the insulators during a normal brake job. They get soaked with goo, baked cracked. They are there to solve a problem that we don't really have. Use them right instead of looking for a crutch and life is simpler. Anyway, that heat has to go somewhere.
To better match the brake system to the task of stopping the weight of a loaded RV6A, I checked the Cleveland brake application chart.
When it came time to replace my discs, I installed discs that were 50% thicker. It was a very low cost conversion. I made my own spacers, and purchased longer bolts and used Rapco discs. Do check clearance on inside bracket.
More weight..... cooler brakes.....less pad wear.
When it came time to replace my discs, I installed discs that were 50% thicker. It was a very low cost conversion. I made my own spacers, and purchased longer bolts and used Rapco discs. Do check clearance on inside bracket.
More weight..... cooler brakes.....less pad wear.
Dennis, you also need to make spacers for the calipers, to allow for the wider rotors. FYI, you can also get wider rotors second hand and machine them down. That will save you some money. Lots of good info on this modification starting here.
http://www.vansairforce.com/community/showthread.php?t=31732&highlight=Brake+upgrade&page=2
The link above gives part numbers, explanations and web links on where to find this stuff. There is also a photo of the DIY spacers for the calipers.
Charlie
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The search function is your friend, as brake issues are an old subject.
The engineered path to heavy duty brakes on a 4, 6, 7, or 8 is a Cleveland 199-93 upgrade kit for the standard 199-102 brake supplied from Vans. The kit adds heat storage mass to the rotor, which increases the kinetic energy rating from 117,500 to 155,000 ft-lbs.
http://www.aircraftspruce.com/catalog/lgpages/cleve_heavydutywb.php
I've installed and flown the kit on an A-model. There is a significant improvement in brake feel and required pedal pressure in the latter part of a landing roll out. I'll install the thicker rotors on my tailwheel 8 if I ever need to replace the disks. They do add a few pounds.
A set of viton caliper o-rings increases the maximum service temperature.
Swapping from 5606 to 83282 brake fluid increases the flash point in the event of a leak, and requires no other change, not even a flush...they're entirely compatible fluids.
I purchased my Rapco HD discs 2 years ago for about $80 each.....
Also need 4 longer bolts.... $3.00 and 2 shims.... $4.00. I don't have the part # for the discs with me, but it is not hard to figure out the correct ones.
There are people that will say they can skid their tires with stock discs. A locked brake produces no heat. And a skidding tire is not the best way to stop. An emergency stop will produce more heat than the stock disc can adsorb. That's why the thicker disc.
Also need 4 longer bolts.... $3.00 and 2 shims.... $4.00. I don't have the part # for the discs with me, but it is not hard to figure out the correct ones.
There are people that will say they can skid their tires with stock discs. A locked brake produces no heat. And a skidding tire is not the best way to stop. An emergency stop will produce more heat than the stock disc can adsorb. That's why the thicker disc.
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R. Daniels
Well Known Member
But.......why? These brakes calipers and rotors are perfectly fine for RV's. I fly off a 2500 foot strip and hardly use the brakes at all. If I do land long and have to use some moderately heavy braking there is never a problem. Why bother with modifying something that works?
It's a reasonable question in the case of thicker rotors. The increased disk mass adds kinetic energy capability that you may never need in your particular type of operation.
Viton o-rings and 83282 fluid are simply better materials with no downside. One makes a leak less likely. The other makes it less likely to burn if it does leak.
