'92 4x4 Brakes to the floor - Wrong Rotors?
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03-03-2008, 04:09 PM
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'92 4x4 Brakes to the floor - Wrong Rotors?
At the end of January I acquired this here F150:
It's a 1992 4x4 extended cab, custom, with the 302 V8. It's been a bit of a rocky start with the truck, but I'm fairly confident I'm getting to the end of its gremlins. There is one slightly dangerous issue I have with the braking system, however, that I'd like to solve asap!
My truck has the habit of spitting out the inboard front brake pads. As you might imagine, without a brake pad between the caliper and the rotor, three things happen; 1) the brake pedal goes to the floor. 2) you destroy the rotor and the piston as they drag against each other. 3) You actually don't have any brakes when this happens.
Upon close inspection of my truck last night I've come to the conclusion that it may have the wrong rotors on it, or I'm missing a spacer. Even with brand new pads installed, they are just _barely_ hanging into the carrier. The brake pad needs to wear just 1/16" or less before it will break free of the carrier under braking. If you ignore this first problem and install the caliper anyways, it sits all the way 'out' on its sliders, leading me to believe I have a part compatibility issue.
Can anyone tell me what the proper Hat offset is for the rotors on this truck?
Brembo's parts catalog (which is _usually_ trustworthy) says the brake rotor should be 68.7mm total thickness. If you were to place the rotor on your workbench, the top of the hat would be 68.7mm off the workbench surface. Is this the correct measurement?
From working on other Ford's I'm aware that often there were part changes throughout the year ranges that may or may not work together. Based on visual condition I would suspect my truck has the same carriers it left the factory with, the calipers appear to be a correct and perfect match to the carriers. This leaves me with a few possible options as to what my problem is:
1) incorrect rotors.
2) missing spacer between rotor and hub.
3) Something else I'm not thinking of.
Thoughts?
*edit* www.1stfordparts.com lists three different rotors for the '92 F150 year. A front rotor for 2wd, a front rotor for 4wd manual locking hubs and a front rotor for 4wd auto hubs. I've got manual hubs, and the rotor is listed as fitting _only_ 1992's. The auto hub rotor fits '92-'94.
I might be answering my own question...
-Dave
It's a 1992 4x4 extended cab, custom, with the 302 V8. It's been a bit of a rocky start with the truck, but I'm fairly confident I'm getting to the end of its gremlins. There is one slightly dangerous issue I have with the braking system, however, that I'd like to solve asap!
My truck has the habit of spitting out the inboard front brake pads. As you might imagine, without a brake pad between the caliper and the rotor, three things happen; 1) the brake pedal goes to the floor. 2) you destroy the rotor and the piston as they drag against each other. 3) You actually don't have any brakes when this happens.
Upon close inspection of my truck last night I've come to the conclusion that it may have the wrong rotors on it, or I'm missing a spacer. Even with brand new pads installed, they are just _barely_ hanging into the carrier. The brake pad needs to wear just 1/16" or less before it will break free of the carrier under braking. If you ignore this first problem and install the caliper anyways, it sits all the way 'out' on its sliders, leading me to believe I have a part compatibility issue.
Can anyone tell me what the proper Hat offset is for the rotors on this truck?
Brembo's parts catalog (which is _usually_ trustworthy) says the brake rotor should be 68.7mm total thickness. If you were to place the rotor on your workbench, the top of the hat would be 68.7mm off the workbench surface. Is this the correct measurement?
From working on other Ford's I'm aware that often there were part changes throughout the year ranges that may or may not work together. Based on visual condition I would suspect my truck has the same carriers it left the factory with, the calipers appear to be a correct and perfect match to the carriers. This leaves me with a few possible options as to what my problem is:
1) incorrect rotors.
2) missing spacer between rotor and hub.
3) Something else I'm not thinking of.
Thoughts?
*edit* www.1stfordparts.com lists three different rotors for the '92 F150 year. A front rotor for 2wd, a front rotor for 4wd manual locking hubs and a front rotor for 4wd auto hubs. I've got manual hubs, and the rotor is listed as fitting _only_ 1992's. The auto hub rotor fits '92-'94.
I might be answering my own question...
-Dave
Last edited by owdlvr; 03-03-2008 at 04:25 PM.
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03-03-2008, 05:02 PM
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03-03-2008, 06:21 PM
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03-03-2008, 08:01 PM
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#5
03-04-2008, 02:00 AM
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Well, after work we yanked the front end apart, here is what we found:
- The driver's side rotor is at least .5" further from the knuckle then the passenger side.
The only way to solve it was by digging in deeper, so I started with pulling the manual hub out of the truck. First clue something has been ****ed around with on the truck: There was no clip on the end of the axle stub, the manual hub was flush with the end. Couldn't push it in further, and it's about .5" off. Second clue that something has been ****ed around with? The outer spring clip was made from a piece of wire...possibly coat hanger. Hmmm..
Our thought by this point was that a bearing wasn't seating properly, and off came the hub. Third clue something has been ****ed around with? The bearings look brand new. Hmmmm. So the bearing races are all set into the hub properly, the bearings fit correctly...but when it's all dry fit, sure enough, .5" off.
So my truck is currently parked in our office shop with the front end in pieces. I have tomorrow morning to figure out at the local wrecking yard if it's the hub, or spindle that has been replaced on my truck...and find the correct ones.
Fords are supposed to be easier then Audis, aren't they? Geesh.
-D
- The driver's side rotor is at least .5" further from the knuckle then the passenger side.
The only way to solve it was by digging in deeper, so I started with pulling the manual hub out of the truck. First clue something has been ****ed around with on the truck: There was no clip on the end of the axle stub, the manual hub was flush with the end. Couldn't push it in further, and it's about .5" off. Second clue that something has been ****ed around with? The outer spring clip was made from a piece of wire...possibly coat hanger. Hmmm..
Our thought by this point was that a bearing wasn't seating properly, and off came the hub. Third clue something has been ****ed around with? The bearings look brand new. Hmmmm. So the bearing races are all set into the hub properly, the bearings fit correctly...but when it's all dry fit, sure enough, .5" off.
So my truck is currently parked in our office shop with the front end in pieces. I have tomorrow morning to figure out at the local wrecking yard if it's the hub, or spindle that has been replaced on my truck...and find the correct ones.
Fords are supposed to be easier then Audis, aren't they? Geesh.
-D
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03-05-2008, 02:32 PM
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