Anyone recently rebuild their front brakes completely?

[bigblock73]

I rebuilt and reassembled my front brakes a while back...after being apart four plus years. When I was almost all done, all I had left to do was put my pads in the calipers and slide the assembly over the rotor...this is when I encountered my problem.

The assembly would fit...the mounting holes on the caliper wouldn't clear the spindle. The outside pad wouldn't allow that to happen. It appeared the pad was too thick or something.

I double checked the rotor, calipers, and pads were correct for my application since these were all new parts from NAPA. Everything checked out correct.

Next, I checked to ensure the bearing in the rotor were seated correctly over the spindle...this was OK as well.

Well, after lots of thought and scratching my head, I pulled everything back apart again and started over.

This is when I realized the seal that sits inside the backing plate hole was the culprit. The seal was basically too thick and did not allow the rotor to slide all the way onto the spindle...and also caused drag when trying to rotate the rotor. Once I realized this, I remember it looking different that the original I pulled out four years ago.

Now for my question.

Is this seal necessary???

With the seal out, the rotor spins freely, and more importantly, everything seems to fit together perfect.

Just wondering what you guys did, or would do in my situation.

Sorry for the long post by the way.

[1987 Shortwide]

I really wish I remembered how mine worked, since I did it recently, but it went together flawlessly.

[Russell]

Jeff, can you get a picture of the seal in question?

[bigblock73]

Russell, I'll snap a pic tomorrow night when I do the other side.

Steven, did you have the backing plates off? If so, do you remember there being a rubber seal on there, or did you replace it when you re did them?

[1987 Shortwide]

I'll go out and look at it closer tommorrow if I have a chance.

[79BIG10]

Jeff when I redid the front end I redid the brakes and the seal to keep the bearings in place fit snug. I had to tap in it flush with a hammer. Could it be that the bearings aren't sitting flush with the inner races?


Edit: You're talking about the other seal but this seal I just talked about might be a problem as well.

[boxrodz]

Jeff-
I don't quite follow your description. I've included a diagram of the front brakes. I'm not sure if you're talking 'bout the 'rubber' bushings (3) or the sleeves (2) or ???. If you are referring to this, I would maintain them in your setup. (I'm guessing that it helps with the movement of the brakes and also reduces the niose.) Lube them with some silicon grease or brake lube and try again. You should be able to reposition the sleeves to clear the spindle mounting points when installing the caliper assemby. (BTW, I'm sure you also have the piston push all the way into the bore.)

[bigblock73]

This is a rubber seal that slips in the round opening on the metal backing plate. The backing plate slides over the spindle and bolts to its cast iron uprights. The whole backing plate assembly is behind the rotor and bolted to the spindle.

I'll get pics tonight.

[Tx Firefighter]

That rubber gasket behind the backing plate is very thin. If it's causing the brake to rub, your backing plate must be bent so it's too close to the rotor.

[bigblock73]

Originally Posted by Tx Firefighter

That rubber gasket behind the backing plate is very thin. If it's causing the brake to rub, your backing plate must be bent so it's too close to the rotor.

TX, the one I pulled out was very thin...on the inside and outside. When I purchased new ones, one side was very thin, the other side was about an 1/8" thick. I tried to install it both ways, but both times it still had drag on it when I put on the rotor. NAPA assures me this is the part I need...not so sure I agree

When I get home, I'll pull apart the drivers side and check it out...and take pics.

I do know the backing pates are not bent...as I have inspected and painted them.

Do I need those seals, what exactly do they do? Just an axtra layer of protection from allowing dirt/debris between it and the rotor?

Should the rotor spin pretty easy when assemble correctly? With the seal in, I can't spin it easily at all, with it out...I can spin it and it will go about 1/4 the way around before it stops.

[Tx Firefighter]

I just this weekend put new spindles and 75 model brakes on my Suburban, so I dealt with this stuff recently.

My little rubber seal washers were beat, so I just put a thin bead of silicone onto the spindle and bolted the backing plate onto the spindle. The silicone flattened out and no problems with interference.

[bigblock73]

Thanks for the tip TX, I will be doing that it I can't figure out whats up with them little buggers.

[cutter61]

i replaced my splash shields(backing plate) as well and got them from the dealer,they were so bad they were like swiss cheese and scraping the rotor-when i received them there was no seals at all so i asked about them-they could'nt even get them anymore so they suggested using hardened gasket sealer between them and the spindle-there was alot of old dirt and crap on the seat of the spindle that was'nt letting them sit properly-cleaned them up and put a small bead on there and it is leak proof now,just had to make sure none squeezed out the front onto the spindle-like TX said,silicone them and you should'nt have a problem

[86 GMG]

Originally Posted by Tx Firefighter

I just this weekend put new spindles and 75 model brakes on my Suburban, so I dealt with this stuff recently.

My little rubber seal washers were beat, so I just put a thin bead of silicone onto the spindle and bolted the backing plate onto the spindle. The silicone flattened out and no problems with interference.

this is what i did as well!

[Tx Firefighter]

Here's the pics I took when doing the job.

[powder2]

hey i just replacedd all of my front brakes rotor bearings and calaper man u would never think that stuff would be so cheap
rotor was 39.95
calaper was 13.95
bearings were 6.95
it all went on smooth

[bigblock73]

OK, here is a pic of the seal in question.

I ended up doing what most of you did, used a bead of silicone between the backing plate and spindle. Wish I would have thought of that sooner.

I am still having a problem with the drivers side.

The passenger side went together flawlessly, it almost assembled itself...but the drivers side it being a beoch! With the rotor on, everything tightened down to specs, I cannot slide the caliper assembly over it. I can get it on if I hammer it on with my hand, but then the rotor will not spin...and I am worried this could be a problem. Basically, the caliper wont slide over the spindle mounting point...the outer pad is preventing this.

Could it just be the tolerances are slightly off on this side (pad, rotor, or spindle)?? Should I go ahead and assemble it and hope that once the truck is driveable it will wear down the pad enough that it won't matter?

I might be overthinking this, but I want to finish this, move on to the next item on the list, and not look back.

What do you guys think?

[swervin ervin]

Jeff,

have you pushed the piston back in the caliper as far as it will go?

[bigblock73]

Originally Posted by swervin ervin

Jeff,

have you pushed the piston back in the caliper as far as it will go?

Yup, it is all the way in.

I did go and purchase all new bearings again for this side, I am starting to wonder if one of the bearings is not allowing the rotor to seal all the way.

I think I will try and get them in tomorrow night.

Does this sound like a possibility?

[swervin ervin]

Other than that, the only thing I can think of is maybe wrong pads or calipers.

[bigblock73]

Definately not the wrong pads or calipers, the pass side went together perfect.

If the new bearings don't fix the problem, would it be OK to assemble it tight like I mentioned? The outside pad will wear down, I just don't want to warp the rotor or cause any other problems in the process.

[boxrodz]

I follow you now.

I didn't have any problems with the dust shields and was fortunate that the rubber seals not deterioring yet. (Thanks for the silicon tip, Tx. Being silicon, I suppose it can handle any excessive brake/rotor heat. Probably doesn't get too hot anyway.)

Like you, I'm wondering if the bearings not seated correctly. If you haven't already done so, I'd probably compare the driverside and the passenger side rotors/bearings. BTW, what size rotors are you running (1" or 1 1/4"). I have an old set of 1" rotors with the bearings still installed if you need pics.

[85X3]

Not very wise to run it tight. Rotor will generate massive heat eventually cooking bearing grease, warping new rotor, and stinking too. Pads are not designed to wear down fast. Are both rotors same thickness? New calipers?
If not, did you send the piston home with a C-clamp?

[Tx Firefighter]

With the rotor laying on the floor, will the caliper and pads slide onto it then?

I'd not think it's a bearing problem if the spindle nut threads on far enough to allow the cotter pin to go through the hole.

[bigblock73]

Yes, the caliper w/pads will slide over the rotor when off the truck. The problem was that when I went to slide the caliper w/pads over the rotor when on the truck, the spindle mounting tab stuck out (less then 1/16")...not allowing the caliper to slide on smoothly. This could be the pads fault (slightly too thick), or the spindle or caliper tolerances slightly off. To remedy the problem, I ground off a little of the caliper mounting surface...and it slides on smoothly now. I hope this makes sense, and most importantly, I do appreciate everyones effort in helping me here on this problem.