Rear rotors clunking after drum/disc brake conversion

[Guanfy]

So I noticed on my test drives after the swap that I was getting clunking. Upon further inspection I identified the rotor is clunking because the rotor holes are a little oversized compared the to lug studs. Normally this isn't a problem as the rotor hat gets compressed by the lug nuts and locks the rotor in position. However... even when torquing open lugs at 100 ft-lbs the rotor is still clunking freely. So to the others on the forum who have done this, did you have this same issue? Was your solution to use spacers to make up the difference to lock the rotor hat in place? Did you use a wheel spacer to convert it to lug centric? I bought decent rotors new for a 2000 Mustang v6, which should be compatible with this mod. The axle they are being bolted to is a 2007 ranger 8.8 axle.

 

[Ranger850]

Why not get rotors for an 07 Ranger? 00 Musrang is 7 years older and things could have changed.
When I worked at the brake shop, Jake's Brakes,I dated a girl who drove a 00 v6 mustang convertible 35th anniversary edition. Also a changover year for some very specific parts. I know because I couldn't find the correct components until i specified the "35th anniversary"part. That made it a midyear edition like the 65&1/2 mustang.

 

[Guanfy]

Swap directions call out for using Mustang calipers and rotors and pads from any model year between '94-2004.

 

[Guanfy]

I believe Mustang because you need the backing brackets from a mustang to pull this off, so the rest of it needs to be mustang hardware.

 

[don4331]

Why not get rotors for an 07 Ranger? 00 Mustang is 7 years older and things could have changed.
When I worked at the brake shop, Jake's Brakes,I dated a girl who drove a 00 v6 mustang convertible 35th anniversary edition. Also a change over year for some very specific parts. I know because I couldn't find the correct components until i specified the "35th anniversary"part. That made it a midyear edition like the 65&1/2 mustang.

Ranger's don't get rear rotors until '10, and then they are more like a vented version of the Explorer rotor (i.e. drum brake in hat for parking) than Mustang with parking brake in caliper.

So I noticed on my test drives after the swap that I was getting clunking. Upon further inspection I identified the rotor is clunking because the rotor holes are a little oversized compared the to lug studs. Normally this isn't a problem as the rotor hat gets compressed by the lug nuts and locks the rotor in position. However... even when torquing open lugs at 100 ft-lbs the rotor is still clunking freely. So to the others on the forum who have done this, did you have this same issue? Was your solution to use spacers to make up the difference to lock the rotor hat in place? Did you use a wheel spacer to convert it to lug centric? I bought decent rotors new for a 2000 Mustang v6, which should be compatible with this mod. The axle they are being bolted to is a 2007 ranger 8.8 axle.

1st question - when you install the rotor on the axle, is it tight against axle flange?
2nd - if you leave calipers off, do your rims bolt tight to the rotors?

I had no issues with axle flange/rotor/rim combination being tight together.

Can I get pictures of caliper mount on axle?

p.s. One critical item for this implementation - remove the check valve for the rear brakes. Drum brakes keep 10-20 psi pressure in lines to balance the springs holding drums in place, so they activate responsively. Discs only need a couple psi. If you don't remove the check valve, it will eat pads/rotors like candy.

 

[Guanfy]

Ranger's don't get rear rotors until '10, and then they are more like a vented version of the Explorer rotor (i.e. drum brake in hat for parking) than Mustang with parking brake in caliper.



1st question - when you install the rotor on the axle, is it tight against axle flange?
2nd - if you leave calipers off, do your rims bolt tight to the rotors?

I had no issues with axle flange/rotor/rim combination being tight together.

Can I get pictures of caliper mount on axle?

p.s. One critical item for this implementation - remove the check valve for the rear brakes. Drum brakes keep 10-20 psi pressure in lines to balance the springs holding drums in place, so they activate responsively. Discs only need a couple psi. If you don't remove the check valve, it will eat pads/rotors like candy.

1. By install, do you mean with the caliper attached? When the rotor is on and the caliper attached and loaded, there is a small amount of play in the rotor.

2. I'll test this tomorrow.

3. I'll get this to you tomorrow.

4. Where does one find a rear check valve for the brakes?

 

[don4331]

4. Look at Guaknar's post just prior to yours.

1. I was thinking we would start with no caliper. Rotor should be tight on axle flange - I want to make sure you aren't dealing with warped rotor and/or axle flange.

 

[Guanfy]

4. Look at Guaknar's post just prior to yours.

1. I was thinking we would start with no caliper. Rotor should be tight on axle flange - I want to make sure you aren't dealing with warped rotor and/or axle flange.

I'm seeing identical behavior out of both sides if that helps your thinking cap.

 

[Guanfy]

p.s. One critical item for this implementation - remove the check valve for the rear brakes. Drum brakes keep 10-20 psi pressure in lines to balance the springs holding drums in place, so they activate responsively. Discs only need a couple psi. If you don't remove the check valve, it will eat pads/rotors like candy.

I checked that thread. By check valve you mean the proportioning valve, correct?

 

[don4331]

It's a RABS/Check valve; it isn't really a proportioning valve. It's probably best to "shorten" the spring a little than to remove completely - rear wheels locking 1st is bad...

If you tighten rotors down on axle flange with no rims on, and no pads in calipers, is the rotor centered in the caliper?

If you tighten rims to axle flange without rotors, will it seat tight.

Trying to figure out where it is getting hung up.

 

[Guanfy]

It's a RABS/Check valve; it isn't really a proportioning valve. It's probably best to "shorten" the spring a little than to remove completely - rear wheels locking 1st is bad...

If you tighten rotors down on axle flange with no rims on, and no pads in calipers, is the rotor centered in the caliper?

If you tighten rims to axle flange without rotors, will it seat tight.

Trying to figure out where it is getting hung up.

I'm going to need to pull a diagram of the proportioning valve and see where this spring you speak of is. I'll go back and check that other thread as he has a nice exploded picture of his assembly all apart. It's night in my part of the world so I'll get working on the rotor fitment tests tomorrow when I have some sun.

 

[Guanfy]

Alrighty, quick update. I got some time to test stuff today and identified the issue as the caliper. There are no clearance issues per say, but when the caliper is mounted and loaded the rotor hat no longer is the source of compressive force holding the rotor, the caliper is. I think what is happening is that the rotor is being slightly tilted when positioned inside the loaded caliper which is preventing the rotor from seating. I'm noticing when I take the lugs off the tire from testing that some of the lugs are tighter than others even though they are all torqued to the same number. Next steps for me are to get some grade 8 washers from the local hardware store and use them as spacers on the caliper bracket. I"m hoping that I can space the bracket out just enough that the rotor become true again and the rotor hat can do the clamping force again. I have some grade 8 bolts left over from a leaf spring upgrade that fit the caliper brackets but are a few threads longer than what came off the mustang that I'll use so that extra few washers don't endanger anything. I'll post an update once I do some tinkering.

 

[Guanfy]

2nd update:

I've found the main issue. The 8.8 axle has a larger center ring on it than the 7.5 that came out. As a result, my stock 14in rim will not fit on the bigger axle end. I can either grind something to fit or upgrade to 15in rims and tires. I'm choosing to upgrade to get the benefits and selection that comes from moving to a 15in rim versus a 14 inch.

I did also find that when I snugged the rotor down tight with lug nuts and no tire the rotor's happy place left a very small gap between the backing plate and the caliper bracket. I slid a grade 8 hardened washer in that gap and it fits rather nicely. I think once I upgrade to the 15 inch rim that should resolve this issue.

 

[MikeG]

14" rims (stink), got rid of mine within a year or two. Much better and sometimes cheaper tire selection with 15s.

 

[Ranger850]

16's are even more common than 15's now. Might as well jump on up to 16" Ford has been using 16" rims since the mid 90's, so they are out there.
Here is a very common Ranger wheel in 16"

I like these