New rotors and pads-question


#1

I have installed new rotor/hubs, and pads on my Ford Econoline.Test drives well,solid feel at the pedal. I pulled the wheels this morning after a short drive, the hubs were pretty hot, and it feels like the pads are dragging on the rotor. I previously removed some fluid from the reservoir when I did the install to allow for the thicker pads.Looking through the “window” on the caliper,the piston looks just about fully retracted already. Do I need to remove more fluid or is this to be expected with new pads? Any help would be appreciated. Thanks.


#2

What year is your truck? Does it have self-adjusting brakes?


#3

Hmm… I thought all disc brakes are self-adjusting.


#4

This van is a 2001 E150 with 4W ABS. I think the rear shoes are self adjusting but I don’t know about the front disks. When I re-installed the calipers with the new pads, I had the piston retracted, and there was plenty of freeplay at the hub, so I think the piston has more room to go…


#5

Did you push the old fluid out of the calipers back into the ABS system and master cylinder?? That’s NOT the way to do it…You should have opened the bleeders and discarded the fluid, not forced old, dirty fluid back into the system…

Also, I have seen the rubber flex-hoses swell up internally and act like one-way check valves, causing the brakes to drag…And…The calipers are supposed to be able to “float” on their mounts. Make sure they are not sticking and jamming on their mounting pins or slides…


#6

Caddyman, I understand about the bleeding process, but I was by myself, and had a badly warped rotor that I was anxious to replace, so I pressed the piston back for now, and plan to get a complete fluid replacement soon. The calipers did float when I first put them on.


#7

Double check your work and make sure you didn’t install the caliper(s) with a twist in the hose. This will make your calipers drag because it puts a kink in the hose. You may also want to replace your hoses anyway due to age and the fact that you had a badly warped rotor. A restriction in the hose may very well be what caused that badly warped rotor in the first place. If your hoses have a steel bracket that wraps around the hose itself, corrosion of the bracket will often cause the hose to become constricted. The solution is to replace the hose.


#8

You’re in normal territory. The amount of fluid in the master cylinder makes no difference to the pads and calipers. A smooth, straight rotor won’t push the pads away, so you will always have some heat. Disc brakes need no adjustment.


#9

Mark9207, I think the hoses look ok, the final connection over the bleed screw being a metal section. Taking Caddymans suggestion, I got a vacuum bleeder kit at Sears, sealed all the connections, pumped it up to about 20 psi and took plenty of fluid out through the bleeder, dropping the level about a 1/2 inch in the reservoir. I haven’t pumped the system back up, but the piston still hasn’t moved. Its seems too tight, with really no freeplay at the hub. I can spin it, but it wont continue to spin on its own, which doesn’t seem right to me.


#10

I never said a THING about BLEEDING the brakes…I simply said that when you retract a caliper piston, you should open the bleeder so the fluid can escape and not be forced back into the system…That’s not bleeding the brakes…

Caliper pistons are not that free to move in their bores…After you set the brakes, they will indeed drag and not be free-turning. What causes the the caliper piston to be pushed back a few thousands of an inch is the normal play in the wheel bearings which allows the rotors to wiggle ever so slightly and push the caliper piston back just enough for the wheels to become free-turning…But up on jack-stands, that will not happen and the brakes WILL drag a little. Perfectly normal. Try this. With the tire, hub and wheel off the ground, step on the brake. Then try to turn the wheel. It will have a considerable amount of drag. Then whack the tire with a baseball bat, something like that to simulate a driving impact on the wheel. The wheel should now turn MUCH more freely as the caliper piston has been jarred back just enough to release the brake…


#11

Caddyman, I thought you were saying that removing fluid through the bleeder would allow the piston to retract on its own,instead of having to push it back, so I misunderstood. On the plus side I have a great new tool ! As pleasedodgevan2 and yourself have said, the constant friction between pad and rotor is normal. Thanks for all your input.


#12

Brake Job Tips: Hose Clamp; ABS Sensors.
Forcing Dirty Fluid Back into the ABS:
[From Motor Service Magazine] “We believe the biggest brake bungle techs are making today is forcing caliper pistons back without clamping the hose and opening the bleeder. Since the line comes in near the bottom of the cylinder where the sediment is, this forces debris up into the ABS unit, and that will likely result in a comeback for a glowing anti-lock warning light. Just opening the bleeder as you may have done in the past isn’t good enough anymore. You’ve got to choke off that hose.” [Editor’s note: you can buy inexpensive plastic pliers with rounded jaws designed to clamp rubber brake hoses without damage. Check your auto parts store.]

I use “needle nose” vice-grip pliers with 5 cm pieces of rubber gas lines slipped over the jaws to block the gas lines.

You can also buy, from Sears, online only: 2 Pc Fuel Line Clamps from OTC,
Sears Item# 00970993000 | Model# 4506, for about $10.


#13

Did you clean the rust off the caliper slides and use silicone grease on them? The square cut O-ring in the caliper is supposed to provide enough spring-back to slightly retract the pads but everything has to be working like new for that to happen.


#14

You mention ‘the hubs.’ You mean both front hubs? or just one side? I do check hub temp after i drive after a brake job. Are the hubs hot or warm to the touch? do they cool down within say 15 minutes? or are they too hot to touch and stay that way for longer than 15? too hot hubs indicate either a bad wheel bearing, or a hanging brake pad. Since you just did a brake job that is what I would suspect. But brake use DOES make hot hubs in normal use. are they both (relatively) equal in temp? Or is one side hotter, and stays hotter longer? Did you (upon reinspection) ensure that all pads are on straight, and equal?

The short list when doing a brake job (without getting too technical) remove, clean 1. piston clean the exposed piston, and the area around the seal, Prior to jamming crud back into the rubber seal 2. Clean brake pad slide guides of rust and debris. 3. clean and lube caliper slide pins (or replace) But I have NEVER found after market pins as good as OEM pins. make sure the rubbers are ‘snapped’ back into place to keep dirt out. 4. grease caliper slides. 5 use pad adhesive to stick the pads to the caliper piston and caliper. Just make sure none gets on the piston or on the surface of the pads 6. (probably the most important to instant satisfaction) clean the rotors with the good quality brake parts cleaner to remove ALL dirt, grease and hand prints from the rotor PRIOR to initial use.

The last one is really important to get the pads to seat in correctly, with no noise, and good stopping power, right from the start.

#5 is my personal preference. I don’t like chattering pads. I can hear them and it bugs me when I can hear them.


#15

To Mechaniker,oldtimer 11, and cappy208,

Great comments/advice, thanks for taking the time to help. Now I’ve got more work to do on those brakes !