Brake information please

[mikeavison]

Fitting new tyres I noticed the calipers are not free to slide when the pads wear. From what I can see it seems like the sleeves in the black painted axle plate should slide freely in the plate ( see Photo hopefully.) Ours are locked solid on both sides. Does anyone know if I am right, should the sleeves slide freely or are they pressed in.

 

 

[mikeavison]

picture of axle plate and sleeves

[mikeavison]

 

Fitting new tyres I noticed the calipers are not free to slide when the pads wear. From what I can see it seems like the sleeves in the black painted axle plate should slide freely in the plate ( see Photo hopefully.) Ours are locked solid on both sides. Does anyone know if I am right, should the sleeves slide freely or are they pressed in.

[Head in the clouds]

[ATTACH=full]50220[/ATTACH]

It's hard to tell much from the limited info and photo.

 

What brand are the brakes? Are they floating caliper type or floating disc type?

 

If they're the first type then the caliper should float sideways on pins or on the axle to compensate for uneven wear between the inner and outer pad. If they're the latter type then the caliper remains fixed and the rotor (disc) floats sideways on the pins.

 

Either way they can be fitted (or designed) wrongly - here's a link to a post I wrote on HBA about the incorrect design and fitting of the otherwise excellent Black Max brakes - Black Max Brakes

 

 

[mikeavison]

It's hard to tell much from the limited info and photo.What brand are the brakes? Are they floating caliper type or floating disc type?

 

If they're the first type then the caliper should float sideways on pins or on the axle to compensate for uneven wear between the inner and outer pad. If they're the latter type then the caliper remains fixed and the rotor (disc) floats sideways on the pins.

 

Either way they can be fitted (or designed) wrongly - here's a link to a post I wrote on HBA about the incorrect design and fitting of the otherwise excellent Black Max brakes - Black Max Brakes

Hi Head in the Clouds,

 

The discs definitely don't float, so I guess the calipers are supposed to. I had not appreciated that many types of brake have been fitted to Savannahs, I imagined just one had and so anyone reading the post who had dismantled one would recognise the picture, and tell me if they had considered the same question. And hopefully arrived at the correct answer. The shiny metal sleeves you can see in the picture, when assembled have bolts through them which hold the piston on one side and the static pad on the other side. So if those sleeves were free to slide in the black metal axle plate, the caliper itself would be able to float. So to my mind this seemed the intention of the design. Our problem arose because all four sleeves ( 2 on each wheel), were locked solid in the black axle plate. We tried some gentle persuasion on 2 of them with no success at all. There was no visible corrosion on either part, so it rather seemed as though they were an interference fit. This seemed contrary to my idea of how they should work, as explained above.

 

Thanks for your advice.

 

 

[mikeavison]

It's hard to tell much from the limited info and photo.What brand are the brakes? Are they floating caliper type or floating disc type?

 

If they're the first type then the caliper should float sideways on pins or on the axle to compensate for uneven wear between the inner and outer pad. If they're the latter type then the caliper remains fixed and the rotor (disc) floats sideways on the pins.

 

Either way they can be fitted (or designed) wrongly - here's a link to a post I wrote on HBA about the incorrect design and fitting of the otherwise excellent Black Max brakes - Black Max Brakes

Hi Head in the Clouds,

 

The discs definitely don't float, so I guess the calipers are supposed to. I had not appreciated that many types of brake have been fitted to Savannahs, I imagined just one had and so anyone reading the post who had dismantled one would recognise the picture, and tell me if they had considered the same question. And hopefully arrived at the correct answer. The shiny metal sleeves you can see in the picture, when assembled have bolts through them which hold the piston on one side and the static pad on the other side. So if those sleeves were free to slide in the black metal axle plate, the caliper itself would be able to float. So to my mind this seemed the intention of the design. Our problem arose because all four sleeves ( 2 on each wheel), were locked solid in the black axle plate. We tried some gentle persuasion on 2 of them with no success at all. There was no visible corrosion on either part, so it rather seemed as though they were an interference fit. This seemed contrary to my idea of how they should work, as explained above.

 

Thanks for your advice.

 

 

[mikeavison]

PS I don't know what brand, there is no writing on them. I'd think they are adapted versions of some other brake repurpossed by ICP the plane kit manufacturer.

 

 

[IBob]

I have a late 2014 S under construction. Brakes appear the same as your pics, and you're absolutely right, those shiny sleeves are supposed to float or slide in the black metal axle plate tubes.

 

(Small difference in what I have is that the black metal tubes are swaged into the plate, not welded like yours, but functionally they should be the same.)

 

 

[mikeavison]

I have a late 2014 S under construction. Brakes appear the same as your pics, and you're absolutely right, those shiny sleeves are supposed to float or slide in the black metal axle plate tubes.(Small difference in what I have is that the black metal tubes are swaged into the plate, not welded like yours, but functionally they should be the same.)

Hi IBob

Thanks for your information that is very helpful.

 

I'd say to you make sure you put a small amount of molybdenum grease on those sleeves they plainly are susceptible to locking up. And re-grease them at every service. Ours are now so tight I think they may be impossible to budge without damaging the sleeve or the plate, and the Sav is not that old. Fortunately the pads hardly wear and for now we have just reassembled it and it works fine.

 

 

[IBob]

Hi IBobThanks for your information that is very helpful.

I'd say to you make sure you put a small amount of molybdenum grease on those sleeves they plainly are susceptible to locking up. And re-grease them at every service. Ours are now so tight I think they may be impossible to budge without damaging the sleeve or the plate, and the Sav is not that old. Fortunately the pads hardly wear and for now we have just reassembled it and it works fine.

I surely will...........

 

 

[Kyle Communications]

The Sav brakes are crappy...poor copy of Matco I think

 

They only JUST work

 

 

[IBob]

The Sav brakes are crappy...poor copy of Matco I thinkThey only JUST work

I was thinking if that were me, I'd sort it out: they'll be even worse now, and the disk isn't designed or mounted to take sideways thrust.

Take them off, soak them in kero or some such for a week, then support the plate flat on a steel block and see if a little hammering via a copper drift won't get things moving....

 

 

[Kyle Communications]

Mabel has larger tyres and I was going to get the brakes to bits and see if I could somehow make them better. Might look into doing something with them. The ones on my XL are crappy..as I said they work but only just although I do have 600/6 tyres on the mains. But the caliper sliding doesnt always happen thats for sure

 

 

[mikeavison]

I was thinking if that were me, I'd sort it out: they'll be even worse now, and the disk isn't designed or mounted to take sideways thrust.Take them off, soak them in kero or some such for a week, then support the plate flat on a steel block and see if a little hammering via a copper drift won't get things moving....

Yes we are going to do that asap.

 

 

[mikeavison]

Mabel has larger tyres and I was going to get the brakes to bits and see if I could somehow make them better. Might look into doing something with them. The ones on my XL are crappy..as I said they work but only just although I do have 600/6 tyres on the mains. But the caliper sliding doesnt always happen thats for sure

Kyle Coms, I can't agree that brakes on our Sav are "crappy". Sure I wish the sliding sleeves hadn't seized but we have never felt that the effectiveness of the brakes was inadequate. I like them much better than the brakes on the Ikarus C42, which have very short pad life.

I don't know if maybe the ones on the Sav XL are different and less effective than the ones on the VG.

 

 

[Yenn]

If your brakes were really efficient there would be the constant worry of digging the prop into the ground.

 

 

[IBob]

Mabel has larger tyres and I was going to get the brakes to bits and see if I could somehow make them better. Might look into doing something with them. The ones on my XL are crappy..as I said they work but only just although I do have 600/6 tyres on the mains. But the caliper sliding doesnt always happen thats for sure

Mark, do you have the welded plates like mikeavison's pics here, or are yours swaged?

 

 

[Kyle Communications]

dont know will have to have a look...I havent been able to do much on Mabel this past 2 weeks...family stuff has got in the way

 

 

[mikeavison]

Hopefully my last post on this subject. We used penetrating oil and a G clamp to drive the sleeves out. There was no sign of corrosion so I think they must have been tight from build, which I don't really understand. Anyway we reamed and greased the holes and hopefully all will will now be well. Thanks everyone, especially ibob

 

 

[IBob]

Hopefully my last post on this subject. We used penetrating oil and a G clamp to drive the sleeves out. There was no sign of corrosion so I think they must have been tight from build, which I don't really understand. Anyway we reamed and greased the holes and hopefully all will will now be well. Thanks everyone, especially ibob

Nice job...and hey, I didn't do anything.

I'm not up to brakes yet, but the kit does seem to come with a few bits that benefit from reaming or opening out, including (so far) the metalwork the upper front undercarriage leg passes through, ditto the rear of the torque tube, and the aileron horns on the mixer...

 

 

[bobcharl]

Have some reservations about grease on the sliding pins. Might be ok if you only operate from Tarmac, but from dirt strips dust could be an issue. I wonder if graphite might be an alternative. Mark, I find your comments about poor brake performance interesting: the brakes on mine will hold the wheels (6.00/6) solid so they will skid along an earthen surface during a full power run up. Could the sliding pins in your brakes be seized (like those of mikeavison) and not applying pressure to both sides of the disc?

 

Regards,

 

Bob