Brakes Dragging/Binding/Locking DIAGRAM NEEDED PLEASE!

[320KPH]

on an M20J,

 

ever since the discs were replaced with Blacksteel branded units. the a/c has been locking up one wheel under normal braking.

 

Could this be a mis-assembly issue or something more serious?

 

cheers

 

320

Edited August 25, 2016 by 320KPH
more info required

[N201MKTurbo]

That's kind of weird, I haven't heard of that happening. Have you looked at the slave cylinders? do they look OK? The slave cylinders have nothing in them except a piston. Maybe the mounting pins are binding and holding the back pad against the disk. Maybe there is some debris in the slave cylinder that is blocking the port when you release brake pressure.

[N601RX]

The dragging could be caused by over tightening the bolts that hold the caliper together. They are very close to the piston and can collapse the aluminum caliper in on the piston causing it to stick. 

[320KPH]

thanks for your suggestions. i thought it may have been one disc not bedding in properly, leading to excessive braking on the other side...

 

anyone have a pic of the assembly to check?

 

Edited August 23, 2016 by 320KPH
additional information

[carusoam]

You might find the brake drawings supplied by the brake and wheel suppliers on line...

Somebody posted them a while ago...

Best regards,

-a-

[320KPH]

OK, wasted an hour searching with no result, apart from having to download a manual (which i can do due to cost of mobile wifi in aus.

 

can anyone help so i can compare the diagram to the assembly?

[triple8s]

There is a small spacer that goes on the axle/spindle, can't remember if it goes on first then the wheel bear or after, but, if it's wrong, your brakes will be draggy and then when you apply them they will hang and stick. Or atleast that's what I think would happen if a person "were" to assemble in the incorrect order. 

[Guest]

Assuming that all of the correct parts were used, new discs and new linings.  It is possible that if the piston area of the caliber is not completely clean the pressure plane and lining will drag on the disc.  

If everything is completely clean you may need to make and add a thin aluminum shim between the calliper and the inner brake pad until a bit of pad material is worn away.  Trace the shape on some sheet aluminum and cut it out.  In some cases there is not enough Clarence between the new disc and the new pads.  

Clarence 

[mooniac15u]

1 hour ago, M20Doc said:

In some cases there is not enough Clarence between the new disc and the new pads.  

Clarence 

When it comes to Mooneys you can never have enough Clarence!

[Bob_Belville]

On 8/22/2016 at 8:03 PM, N601RX said:

The dragging could be caused by over tightening the bolts that hold the caliper together. They are very close to the piston and can collapse the aluminum caliper in on the piston causing it to stick. 

I just replaced the discs and pads on my '66E this week. My A&P instructed me torque the 5/16" bolts to 140 in lb. The assembly needs to be solid and not spring as hydraulic pressure is delivered to the pistons. (Apparently the brakes on some models use 1/4" bolts in which case the torque would be different, 90 "#, I think.

(Disclaimer, I am not an A&P. For the most part I do the work because Lynn stays busy and it's much easier to get 5 minutes from him to check something than to get 2 hours from him to do the whole job himself.)

[Rookie]

On line there is a free parts book with a item break down.

[Guest]

6 hours ago, mooniac15u said:

When it comes to Mooneys you can never have enough Clarence!

Just shows what happens without my glasses on.

Clarence