Technical Brake caliper movement

Looking for some brake help. New disc brake conversion on my 52 Styleline. When bleeding the front passenger side, I noticed the caliper twisting on the bracket, not sliding. Relubed the pins, but still does it. Driver side has no movement at all. Any suggestions?

(I have a video of the caliper movement but can’t upload it)

 

Post some still photos of the setup.

 

First I'd make sure that that bracket is straight and square with the spindle.
Be it drum brake wheel cylinders and shoes or disk brake pieces they don't like to bind up because they are out of perfect alignment. Even something like that extra coat of paint on the bracket where the caliper mounts might cause it to hang up a bit. If the calipers have bushings for the pins make sure that they are in right.

 

Are you sure the rotor is properly seated? What kit did you use?

 

It’s a kit from Speedway Motors.

 

Tried to make a gif from my video. Hope it helps.

 

The silver pins need to have caliper lube on them, the o-rings inside the caliper ears are likely causing A LOT of drag causing your problem.

Edit; I see there is lube now from the GIF, either the spacers are too small OD or the o-rings are too large ID. I have a lot of equipment at my job that uses this set up and for that application I would say it's normal but they can only drive 14 miles per hour max. For a street car it needs to be tightened up. Speedway has had known quality issues for some time, so I guess this is what you will be dealing with. If there are any Delco hardware kits available I would try that.

 

It might be the picture, but it appears the pins are at an angle and not perpendicular to the rotor.

 

upload video to youtube, then post a link to it here, using the "film" icon on the toolbar

 

What @Mr48chevy said, bracket/rotor are not parallel to each other. I'd say bent bracket most likely.

 

Hit the full image button.

 

From the GIF, it looks like there is way too much slop between the pin and holes on the inboard side. It's it missing a guide bushing?

 

“It might be the picture, but it appears the pins are at an angle and not perpendicular to the rotor.”

I agree. In the second pic the pins seem to “spread out”. I would pull the rotor and pads back out and assemble without them. The caliper should slide freely on the pins and give a better idea of what’s happening.

 

Pulled out the pads and the caliper slides freely.

 

It's really hard for us to see how straight the brackets are, because of how photography works. It helps if you zoom way out, and stand back a long ways, when you take the picture...it reduces the "fisheye" effect of a close up lens.

The original rubber rings that fit into the caliper were very hard rubber, perhaps the cheap reproductions are made of soft rubber that lets things move around?

 

Video request. Like the sliding one but rocking / twisting the caliper instead. Ideally at a few points but most importantly at the place the caliper would be with the pads installed

Chris

 

Calipers should float, to an extent. That appears to be a bit too much.

Are these remanufactured GM calipers, or new aftermarket ones?

Carefully measure the distance between the bracket and the rotor.

It must be parallel.

Pull the brackets, install the pins, and make sure that the pins are perpendicular to the brackets.

 

Yeah, cheap calipers seem to miss the mark.

That looks like too much movement.

 

Bracket is square to the rotor by measuring gap in two places. Same dimension as driver side.

 

Not sure how to qualify the calipers, but not remanufactured. Purchased new kit from Speedway, so I am assuming new supply as copy of old design (?). The rear kit I got appeared to be a copy of old Cadillac calipers based on the e-brake mechanism.

FWIW, I had to get a new passenger rear caliper because the e-brake mechanism was faulty and would not adjust properly. Perhaps another faulty caliper.

 

Those are clones of GM Metric calipers. Those were used from about 1978-1988, or so.

Anything GM G-body (Monte Carlo, Malibu, Regal, etc.)

If they were OEM, they would have GM raised on the side.

The clones vairy greatly in quality. I pretty much limit myself to Afco calipers, unless I can score OEM ones.

 

You posted the 'kits' are sourced from SPEEDWAY.

Can you give the KIT PART NUMBERS?

 

I'm with Rattlecanrods, the video shows way too much caliper slop on the pins.

 

Unless the pads are pushed out against the rotors, you may see some non-linear slop going on.

I would make sure the pads are pushed out, I do this right after the bleeding process.

 

https://www.speedwaymotors.com/1949...te-Front-Disc-Brake-Conversion-Kit,74072.html
Part number: 9101954

 

So I measured the holes that the pins go through and there was a small difference, ~0.005” larger on the caliper that is moving/twisting. I couldn’t measure the o-ring groove diameter but reported the numbers to Speedway and they indicated they could send a replacement but haven’t processed the shipment yet. We will see.

 

Are ALL of the o-rings in the caliper ?

There should be four, one in each hole. To me it looks like the outside holes may be missing theirs. Or the o-rings are too thin, soft etc allowing excessive movement.

If they are there I'd almost be tempted to buy a good quality caliper rebuild kit from Napa and replace the o-rings and hardware from the Napa kit onto this caliper and see what happens.

If it fixes the problem I'd buy another kit from Napa and install it in the other caliper just to be on the safe side.....


...

 

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You are describing the inner mounting hole on the caliper? That will do it.

Is it the only mounting hole out of spec on either caliper?

You have to understand that these so-called 'kits' are using CHI-CON SLOPPY COPY calipers and hardware also most likely.

 

The o-rings might not have been in when the pictures were taken, but they are all there. I could not actually measure the groove where the o-ring sits, but rather the diameters on each side of the groove.