Van's Air Force
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Brake hoses
- Thread starter uk_figs
- Start date
LettersFromFlyoverCountry
Well Known Member
Thanks for the feedback and the link, I notice from Dan's site that he says the blue AN fittings are used on the high pressure side (the hoses from the left side brake cylinders to the firewall for example) but this was not obvious to me from the drawings as I was about to install the brass fittings on the cylinders.
Also I have dual brakes and it seems the interconnect between the right side and left side brakes is the plastic tubing which when braking from the right side will carry high pressure from the right brakes to the left brakes which then apply pressure to the brakes themselves.
So my question is which fittings do most people use where?
Also I have dual brakes and it seems the interconnect between the right side and left side brakes is the plastic tubing which when braking from the right side will carry high pressure from the right brakes to the left brakes which then apply pressure to the brakes themselves.
So my question is which fittings do most people use where?
mannanj
Well Known Member
Brake Lines
Dave:
If Van hasn't changed the drawings since I built my 8, I would deviate from them on the brake lines down the gear legs to the brake calipers.
At the caliper end, I used 12 inch long -4 stainless steel braided flex hose on mine. I bought them from my local circle track race car supply store. They have the same 37 degree fittings so you can use your regular AN 90 degree fitting in the caliper.
There have been several reports of the 1/4 inch alum. line work hardening and breaking at the 90 on the caliper. This causes complete brake failure on that side and I've read of at least one fire caused by brake fluid spraying on an overheated brake disc.
Another positive---it allows the caliper to float easier on the pins, improving wear on the discs!
Mannan Thomason
RV-8 N!61RL
Dave:
If Van hasn't changed the drawings since I built my 8, I would deviate from them on the brake lines down the gear legs to the brake calipers.
At the caliper end, I used 12 inch long -4 stainless steel braided flex hose on mine. I bought them from my local circle track race car supply store. They have the same 37 degree fittings so you can use your regular AN 90 degree fitting in the caliper.
There have been several reports of the 1/4 inch alum. line work hardening and breaking at the 90 on the caliper. This causes complete brake failure on that side and I've read of at least one fire caused by brake fluid spraying on an overheated brake disc.
Another positive---it allows the caliper to float easier on the pins, improving wear on the discs!
Mannan Thomason
RV-8 N!61RL
mgomez
Well Known Member
Dan's explanation is also the way I interpreted the drawings...and built mine. I haven't put fluid in yet (still a year or two away from that), but it looks like the drawing, so I think it's right.
I bought some teflon paste sealant at Home Depot for the brass pipe thread fittings, and used only a bit of oil on the AN fittings.
There are two jobs in the brake system that gave me fits...I had to get a couple of A&P buddies to help me. One was the nasty little nipples that go in the nylon tubing. I just couldn't get those suckers into the tubing far enough...ended up buying a bunch of replacements.
The other was assembling my own braided hose. Yeah, I know...should've bought them from Van's. But since I installed a parking brake valve, they would've been custom, so I figured I'd learn how to make my own. Tip: cut them with a cut-off wheel in a Dremel or a die grinder, not a hacksaw.
Unfortunately, the photos on my web site aren't very helpful in either regard.
I'm still curious how the right-hand side brakes work. My feeling is -- as you suggested -- that they pressurize the nylon tubing that goes to the left-hand brakes. So, the obvious question...why aren't those lines braided hose as well?
I bought some teflon paste sealant at Home Depot for the brass pipe thread fittings, and used only a bit of oil on the AN fittings.
There are two jobs in the brake system that gave me fits...I had to get a couple of A&P buddies to help me. One was the nasty little nipples that go in the nylon tubing. I just couldn't get those suckers into the tubing far enough...ended up buying a bunch of replacements.
The other was assembling my own braided hose. Yeah, I know...should've bought them from Van's. But since I installed a parking brake valve, they would've been custom, so I figured I'd learn how to make my own. Tip: cut them with a cut-off wheel in a Dremel or a die grinder, not a hacksaw.
Unfortunately, the photos on my web site aren't very helpful in either regard.
I'm still curious how the right-hand side brakes work. My feeling is -- as you suggested -- that they pressurize the nylon tubing that goes to the left-hand brakes. So, the obvious question...why aren't those lines braided hose as well?
Harvey L. Sorensen
Well Known Member
BRAKE LINES
That nylon tubing that Van supplies is rated for 2500 pounds of pressure while the SS braded hose has a 1000 pound working pressure. I have used this nylon tubing on a homebuilt that started flying in 83 and as yet there has been no problem. Now I like the idea of SS hose down at the brake disks.
just my two bits
That nylon tubing that Van supplies is rated for 2500 pounds of pressure while the SS braded hose has a 1000 pound working pressure. I have used this nylon tubing on a homebuilt that started flying in 83 and as yet there has been no problem. Now I like the idea of SS hose down at the brake disks.
just my two bits
N941WR
Legacy Member
This is a good idea but it doesn't really work on the -7 or -9's; however, it might work on the -7A & -9A's. (I think the -8 and the A's has the line running behind the gear legs, which should work fine.) The reason is the line runs in front of the gear leg and the union you need to transition from solid to flex line will not fit under the leg fairing.mannanj said:
I ended up using flex line from the firewall all the way down the gear leg to the calipers.
Check out this page and scroll down to the 9/15/06 & 12/10/06 entries for pictures and an explination.
az_gila
Well Known Member
Buy Teflon...
If you buy the good teflon SS braided hose from a race car supplier, it is smaller diameter than Vans, can be bought in the even smaller -3 size, and is rated for 3,000 psi, with a 12,000 psi burst pressure...
Typical supplier here... they even have pre-made hoses...
http://www.pegasusautoracing.com/productselection.asp?Product=3260
Why not just use two lengths on each side, with a bulkhead coupling at the fuselage side (-A models)?
gil in Tucson
Harvey L. Sorensen said:
If you buy the good teflon SS braided hose from a race car supplier, it is smaller diameter than Vans, can be bought in the even smaller -3 size, and is rated for 3,000 psi, with a 12,000 psi burst pressure...
Typical supplier here... they even have pre-made hoses...
http://www.pegasusautoracing.com/productselection.asp?Product=3260
Why not just use two lengths on each side, with a bulkhead coupling at the fuselage side (-A models)?
gil in Tucson
randylervold
moderator
Guys, I agree that the -3 teflon/ss lines are the way to go, here's a pic of the bottom end of my installation...
http://www.romeolima.com/RV3works/Airframe/DSC_1024.jpg
the line goes up behind the gear leg then through a 90 degree bulkhead fitting on the firewall, then through the same type of line to the master cylinders. I also recommend using the individual reservoirs sold by Spruce (A-600) rather than the leaky plastic low pressure lines and reservoir provided in the kits.
http://www.romeolima.com/RV3works/Airframe/DSC_1024.jpg
the line goes up behind the gear leg then through a 90 degree bulkhead fitting on the firewall, then through the same type of line to the master cylinders. I also recommend using the individual reservoirs sold by Spruce (A-600) rather than the leaky plastic low pressure lines and reservoir provided in the kits.
Another Teflon Line Routing with Pic
Here's my approach to the brake line thing. It's very secure and avoids any chafing issues. I'm hoping that this remains clear of cowl and engine, but these chicken/egg decisions have to be made sooner or later.
Oh, and please disregard all of that multi-colored spaghetti. I'm pretty sure it's all just spare parts.
Here's my approach to the brake line thing. It's very secure and avoids any chafing issues. I'm hoping that this remains clear of cowl and engine, but these chicken/egg decisions have to be made sooner or later.
Oh, and please disregard all of that multi-colored spaghetti. I'm pretty sure it's all just spare parts.
RV7 Brakes lines
I did recheck the drawings and as mentioned Vans does in fact call out the high pressure fittings for the left side connection to the flex hoses that go to the bulkhead and the brass fittings elsewhere.
After viewing some of the installations in this thread I think I will finalize the layout when my finish kit arrives this month so I can see where the hoses and lines have to go plus I plan to install the Matco brake valve and from the threads here this needs some thought also.
Thanks for the inputs.
I did recheck the drawings and as mentioned Vans does in fact call out the high pressure fittings for the left side connection to the flex hoses that go to the bulkhead and the brass fittings elsewhere.
After viewing some of the installations in this thread I think I will finalize the layout when my finish kit arrives this month so I can see where the hoses and lines have to go plus I plan to install the Matco brake valve and from the threads here this needs some thought also.
Thanks for the inputs.
