05 STS brake feel quest

It's pronounced "chassy." Brakes, suspension...things that make the car fun or a death trap
kevm14
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Re: General STS thread

Post by kevm14 »

Definitely some kind of clanking still from the front end. It seems to be more likely on symmetric bumps and also seems to completely stop when the brakes are applied. So I guess shame on me for not doing a real brake inspection when I had the front wheels off for the terrible anti-roll bar bushing job. I just didn't feel like adding anything else to that job at the time...

Maybe I can be efficient and do a brake flush at the same time I inspect the calipers/pads. I'd really like to improve the brake feel.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: General STS thread

Post by kevm14 »

I did more experimentation with the brake pedal regarding the clanking from the front end. It still seems to go away just by touching the brake pedal lightly. So it must be something related to the calipers or pads. The brake feel isn't great so hopefully nothing is like...falling out. It stops straight and is not getting worse. The good news is I don't think it is suspension, as that feels tight.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: General STS thread

Post by kevm14 »

kevm14 wrote:I did more experimentation with the brake pedal regarding the clanking from the front end. It still seems to go away just by touching the brake pedal lightly. So it must be something related to the calipers or pads. The brake feel isn't great so hopefully nothing is like...falling out. It stops straight and is not getting worse. The good news is I don't think it is suspension, as that feels tight.
Yet further convinced it is brake related. Before driving home yesterday, I stuck my finger through the right front wheel and tried to wiggle the caliper. It wiggled and also made a metallic clank as I did so. And again, every single test I do the noise goes away with a very light touch of the brake pedal. I should probably give this an inspection this weekend right after I do the Ram trans pan/gasket/band adjustment.

On the SRX, I think at least one slide pin had a rubber insert. I wonder if that rubber is toasted on this car or something. I bet I will find something amiss. And I bet it is related to the soft/long brake pedal.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: General STS thread

Post by kevm14 »

Here's a thread that is likely the very same issue I have. His car was only 5 years old with 35k. This is why paying a lot more for a luxury car with lower mileage is often not a good value - a lot of the issues they have were at well under 100k (and may would have been fixed, especially with a CPO car).

http://www.cadillacforums.com/forums/ca ... t-end.html

Lots of failure at his Cadillac dealer. At the bottom of page 3, he experienced success at a Chevrolet dealer:
I can't believe it. It's fixed. No more rattle. Dealer installed caliper brackets, calipers, brake pads and a CV axle and it's gone. Not sure which one fixed it, and don't really care. It's quiet again!!!! After six months, it drives like a Cadillac!!
I bet the CV axle had nothing to do with it. I bet either my pins are loose in the bracket or the pads are loose in the caliper. I may end up doing pads and pins to get rid of it. Wasn't planning on doing brackets but we'll see I guess.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: General STS thread

Post by kevm14 »

http://forum.roadfly.com/threads/128985 ... e-Calipers

lol
2007 CTS Noisy Brake Calipers
2007 CTS Sports suspension large wheels
Brake calipers rattle until slight pressure put on brake pedal. Dealer says it is normal for this model. Anyone have a solution?

Thanks
This was posted in 2009. No response. The 06-07 CTS upgraded to the same dual piston calipers used on the 04-09 SRX and 05-11 STS. So something in the design and OEM parts is stupid.
Bob
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Re: General STS thread

Post by Bob »

One of my friends who owns an Elise had an issue with rattling calipers. I helped him put some of this on the back of the pads and the problem went away. Not sure if this is the same as your issue.
Attachments
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kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: General STS thread

Post by kevm14 »

Inspected the brakes. The pins were definitely loose in the caliper bracket. But everything else looks good. Rotor looks great.
WP_20170610_15_59_35_Pro.jpg
Pads have plenty of meat just as he said.
WP_20170610_15_59_59_Pro.jpg
WP_20170610_15_59_43_Pro.jpg
Dual piston JE5 brakes.
WP_20170610_15_59_51_Pro.jpg
What do I think the problem really is?

Nearly dry slide pins. Yes really.
WP_20170610_16_00_30_Pro.jpg
After cleaning off what little lube there was, I relubed with that Bendix BL20 stuff I like. Sadly, I think it has been discontinued. Not available on Amazon or Summit.
https://www.amazon.com/Bendix-BL20-Cera ... op?ie=UTF8

However, Permatex makes some high performance ceramic stuff that seems to have the same specs.
https://www.permatex.com/products/lubri ... bricant-2/

Anyway, when I slathered the pins with lube and made sure the caliper bracket holes had plenty, not only did they feel really good (slippery) but all that slop was taken up hydraulically by the lube. I think it is supposed to be a little loose to leave room for lube.

Oh, so much for dealer maintenance. I said I was disappointed before and this is the exact kind of thing I am talking about.

Here's the other side. Same deal.
WP_20170610_16_18_56_Pro.jpg
WP_20170610_16_19_01_Pro.jpg
WP_20170610_16_19_23_Pro.jpg
I haven't road tested yet but I'm pretty sure that rattle will be gone. I also think the brake feel will improve. I will have to check the rears tomorrow. I'll report back after the road test after I post this.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

05 STS brake feel quest

Post by kevm14 »

I road tested it.

The feel is better and I think that rattle is gone. The feel is not 100%, which I expected. I will check the rear and eventually do a fluid flush. That SHOULD do it. Car drives damn good anyway.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS brake feel quest

Post by kevm14 »

Did a little errand and the brake feel is definitely improved. Wondering how motivated I'll be today to check the rear. Hot.
kevm14
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Joined: Wed Oct 23, 2013 10:28 pm

Re: 05 STS brake feel quest

Post by kevm14 »

kevm14 wrote:Wondering how motivated I'll be today to check the rear.
Motivated enough. I am kind of a stickler for brake feel and it's not THAT hot yet.

The rear pins were not dry like the front pins but still benefitted from re-lubrication. Based on that, I don't know if the rears were contributing very strongly to the long travel. Probably not. I will judge more tomorrow on my commute.

For what it's worth, in all caliper brackets, the pads were securely installed and did not seem to move around. I did not add anything to the backs of the pads.

Next step: flush and bleed.
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