Brake problems

[FireMedic_2009]

I’ve got a Cleveland 10-9 caliper and a 10-30 Cleveland master cylinder on the pilot side and a Matco MC-4A on the co-pilot side. I rebuilt both master cylinders on the left brake. I’ve bled from the bottom up and have pulled a vacuum on one occasion. The brake isn’t sponging, it just has excessive travel (2”). The right side only travels an 1/8” before it grabs. I noticed after I bleed it, it grabs after 1/8” travel. It even held for a few hours. Next day the 2” travel is back.

The other thing I noticed is it seems the piston on the caliper seems to retract back about a 1/4-3/8” instead of the pads lightly dragging like the right side. I’ve spoken to Cleveland and they said to make sure the peddle is not restricting the master cylinder from fully extending which would case the check valve from fully closing. I removed the bolt at the top clevis hoping that was the problem but the peddle moved forward another 1.5” proving it was restricting the full extension of the master cylinder.

Has anyone had this happen before and know what fixed it or the cause?

Everything would point to the master cylinder but after rebuilding both of them, which I’ve rebuilt a few would any problems, and swapping out both to the pilot side, it’s unexplainable

Thanks

 

[FireMedic_2009]

I found out the problem. I have the narrow wheel pants and it hits the top fitting on the caliper and pushes it towards the wheel so when the brake is released the piston is pushed in. The inside brake pad has a lot more wear than the outside pad

 

[FireMedic_2009]

After cutting a hole in the pants, now it’s hitting the side of the caliper so I’ll add a couple washers between the pants bracket and where it attaches to the axle

 

[RV6_flyer]

That looks like a BRASS compression fitting that would not be the best choice for an aircraft. Yes Van's has used them on plastic / nylon lines but not on aluminum lines.

 

[lr172]

That looks like a BRASS compression fitting that would not be the best choice for an aircraft. Yes Van's has used them on plastic / nylon lines but not on aluminum lines.

Curious as to why you believe brass is incompatible with aluminum tube

 

[FireMedic_2009]

That looks like a BRASS compression fitting that would not be the best choice for an aircraft. Yes Van's has used them on plastic / nylon lines but not on aluminum lines.

I bought the plane a couple years ago after the builder ground looped it 7 yrs ago. I just got the plane flying at the end of Jan.

Nice catch. It didn’t cross my mind about the dissimilar metals and creating corrosion.

Thanks

 

[lr172]

I bought the plane a couple years ago after the builder ground looped it 7 yrs ago. I just got the plane flying at the end of Jan.

Nice catch. It didn’t cross my mind about the dissimilar metals and creating corrosion.

Thanks

Many of us use steel or stainless steel AN fittings on the engine side due to aluminum cracking from vibration and in oil coolers due to al galling the threads. The hose end hardware is typically all aluminum. Stainless steel is even further down the nobility scale from brass. Never seen posts here about corrosion. How significant is the corrosion risk?

 

[FireMedic_2009]

I’m not sure. I did a google search about brass and aluminum and it said aluminum would be the one which would corrode. The plane was built in 2011. I don’t see any signs of corrosion on the aluminum in contact with the brass. I try to use SS on the fuel lines. The plans on the 6 I believe use the compression fitting at the caliper instead of the flared aluminum fitting

 

[lr172]

I’m not sure. I did a google search about brass and aluminum and it said aluminum would be the one which would corrode. The plane was built in 2011. I don’t see any signs of corrosion on the aluminum in contact with the brass. I try to use SS on the fuel lines. The plans on the 6 I believe use the compression fitting at the caliper instead of the flared aluminum fitting

Pretty sure the 6 plans call for flare fittings at the calipar. I just realized that brass fitting was a compression fitting and that should be replaced with a flare fitting. That was probably what rv6 was referencing with his suggestion. Ss in contact with aluminum tube is even further apart on the nobility scale than brass. So if ok with ss and al, you should be ok with brass and al from a corrosion perspective.

 

[RVDan]

FYI braking pressures can be as high as 500 psi. Not typical, but is you are really getting on them. Typical is more like 150 to 200 psi. I got these approximate numbers from a test stand setup with master cylinders, pedals and a seat.