Pantherman

I have a BVM Smoothstop II air valve on my brakes and it is dragging in the brakes off position. I have the servo set to where the cylinder is pushed all the way into the valve body and the brakes are still dragging. Any suggestions for possible cure? It is set up on a JetLegend Hawk with their gear.

Thanks in advance for any advice.

Woody

CARS II

My Feedback: (7)

My solution to the 3 that I had was to pull them out of my airplanes and give them to my good friend John with a ( warning ) use at your own risk, I HAD IT WITH THESE BVM BRAKE VALVES, they work and they don't work even with the best maintenance I could give them and I do maintain my stuff, so now I use a mini air valve with a servo arm on top actuating it and lube on the brakes, guest what, they work all the time every time.

PS: My first and second Fei Bao Hawk have the mini air valve for brakes, very happy with this bullet poof set up.

Harley Condra

My Feedback: (4)

If the plunger is retracted completely into the valve body, no pressure should be applied to the brakes.

To isolate the cause of the problem, remove the pressure line at the Smooth Stop (dumping all pressure fdrom the brake system) and check if the brakes completely release. If they still drag, the cause is the brake o-rings. If this is the case, lube the o-rings with a small amount of vaseline. If not, the Smooth Stop is at fault, leaking a small amount of air into the brake lines.

At any rate, make sure the Smooth Stop plunger o-rings are properly lubed.
If the Smooth Stop is faulty, send it back to BVM for replacement.



Harley Condra
BVM REP
JetCat REP

yeahbaby

My Feedback: (21)

my guess (much like Harley's) is your O-rings have expanded slightly in the drum and although vaseline is a great lubricant providing smooth application of brake pressure to the tires, it has a tendency (in my experience) to cause the O-rings to swell over time.

a light application of some lithium grease will provide the same smooth braking effect as Vaseline mitigating the above effect.

good luck

buck

Kevin Greene

My Feedback: (85)

I thought that the recommended lube was dielectric silicone grease---(Clear, not the white type that is used for heat sinks)---I do know that petroleum based lubes can cause some types of rubber to swell/expand...I've been using the clear dielectric silicone grease for years without issue...

Kevin

S_Ellzey

If you determine that the O-ring is not releasing, another trick to fix that problem is to remove the wheel, apply enough pressue with the smooth stop to expand the O-ring a bit, and then grab the O-ring and spin it around. Some times there is just a dry spot, and this will redistribute the grease that is allready there. This has worked for me several times.

If you still feel that there is air coming from the smooth stop, try this. Disconnect the servo, push the plunger in all the way by hand, pump up the system. Did nothing move? if so, hook a line to the output and put it in a glass of water, if there are no bubbles then there is no leak. If there are bubbles and you have the plunger pushed in all the way in there is a defect and you will need to return the unit, BVM WILL take care of you. I have never seen a unit fail this test, but there is allways a first time. If when you pressurize the system the plunger does move, make sure that you have the line from the air tank going to the plunger. I have seen people get this backwards in a tight installation where they loss track of where everything is going.

If you do need to add grease my favorite is the clear silicon grease that comes in the little round tub that you get from a SCUBA shop, it is very stiff and works very well.

Steven

Pantherman

Thanks for all the tips guys. I did take the servo arm off and push the plunger in by hand to make sure that it is in all the way. I still get the same dragging after the brakes have been applied and released. What makes me think it is a leak is that after letting the plane sit overnight the wheels spin freely, but if I apply the brakes once then the drag when released again. I will try taking off the wheels and lubing the O rings to see if that cures it. If not, I may go back to the stock brake valve supplied and return this one for service. I did verify that the pressure line is attached to the plunger.

Woody

Dawn Ellzey

Woody,

If you are coming to the Austin Jet meet this weekend Steven can take a look at it for you

Dawn

bbjpilot

My Feedback: (2)

"I second CarsII"
My suggestion, remove it!!!! Not worth the headache!! I've tried two, and after spending half of my time removing and re-installing setup at three seperate west coast events I finally decided to replace the "Smooth Stop" with an old reliable button valve(and yes I too used deiletric silicone grease). Enjoyed my day, and never touched a wrench....or lube......or a fine "four" letter word.