Author Topic: Cadillac DTS front brakes sticking and worn strut bearing -  (Read 9186 times)

Online goodfellow

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Cadillac DTS front brakes sticking and worn strut bearing -
« on: September 14, 2019, 07:39:42 PM »
Getting the car ready for a long road trip at the end of the week, and I noticed a few days ago that the front brakes were "clunking" when starting from a stop and when low speed braking. At first I thought it was a stuck caliper, but after a little investigation it turns out to be a slide pin seal issue that was caused by using the wrong grease.





I usually use CRC brake grease on most of my cars, but in this case it's not the right solution. These GM calipers have neoprene bushings on the slide pins and after just a few months since I replaced the brakes, the grease has caused the bushings to swell, and the dust boots to deteriorate. There's something in that brake grease that isn't compatible with these GM designs.

The solution is to remove the caliper bracket and clean it thoroughly in the parts washer, with special attention to the slide pin bores. Then lube with NAPA Syl-Glide silicone based brake grease that doesn't react with the neoprene bushings and cause swelling.









Boots and bushings are deteriorated and swollen -- causing the caliper to stick and clunk.





Everything cleaned and ready for reassembly -









This is not an uncommon problem with these types of GM calipers that use neoprene bushings on the end of the pins to keep the caliper from making noise. Some GM calipers have a single such pin (the other without a bushing), while others have the bushings on both pins.

Although a common problem, I didn't know about it until talking to a pro-tech friend of mine. Learn something new every day  ;)

I also replaced the right front shock/strut assembly because the bearing was making noise. It's a fairly new strut (less than a year old), but NAPA stood behind it. They gave me a replacement without any big drama.

Old one out -



New one in -- not that hard on these old Cadillacs









Monday I'll go for an alignment, and hopefully this DTS is ready for a long road trip at the end of the week.
« Last Edit: September 14, 2019, 08:07:01 PM by goodfellow »

Offline stokester

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #1 on: September 14, 2019, 09:01:59 PM »
<cut>
I usually use CRC brake grease on most of my cars, but in this case it's not the right solution. These GM calipers have neoprene bushings on the slide pins and after just a few months since I replaced the brakes, the grease has caused the bushings to swell, and the dust boots to deteriorate. There's something in that brake grease that isn't compatible with these GM designs.

The solution is to remove the caliper bracket and clean it thoroughly in the parts washer, with special attention to the slide pin bores. Then lube with NAPA Syl-Glide silicone based brake grease that doesn't react with the neoprene bushings and cause swelling.

<cut>
Is the CRC product petroleum based?  This is what I used at the Chevy shop, easy to use with a brush in cap.
« Last Edit: September 14, 2019, 09:04:06 PM by stokester »
Nick
Yorktown, VA

Online goodfellow

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #2 on: September 14, 2019, 09:10:18 PM »
I use the CRC synthetic brake and caliper grease. Been using this for years and haven't had any problems -- BUT have only recently two GM cars in the family fleet; my Caddy and the wife's Traverse. It worked great on the other vehicles.

With the new bushings and the Syl-Glyde, the front brakes are quiet and smooth again.

« Last Edit: September 14, 2019, 09:12:48 PM by goodfellow »

Offline bonneyman

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #3 on: September 15, 2019, 09:39:44 AM »






Dang, Ray, that front end looks super clean! No dirt, crud, or excess grease - just a little rust.

I'd be ashamed to share a pic of my Astro with the front wheel off!  :-\

Offline ron350

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #4 on: September 15, 2019, 12:21:01 PM »
Goodfellow good job catching those swollen bushings.

I tried some of that CRC Synthetic Brake Caliper Grease and it is not compatible with Ethylene Propylene. I have a large piece of Ethylene Propylene that came out of a GM vacuum booster and the CRC Synthetic Brake Caliper Grease made the test spot swell in just a few hours.

All GM brake rubber is supposed to be made from Ethylene Propylene so that brake fluid will not make it swell. Ethylene Propylene is good for brake fluid but can’t tolerate mineral oil of any kind.

It is strange how many products on the market that are supposed to be safe for Ethylene Propylene will make it swell.

« Last Edit: September 15, 2019, 12:22:44 PM by ron350 »

Online goodfellow

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #5 on: September 15, 2019, 09:39:31 PM »

.........It is strange how many products on the market that are supposed to be safe for Ethylene Propylene will make it swell.


Good to know -- thanks Ron!

Online goodfellow

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #6 on: September 17, 2019, 09:46:37 AM »


Dang, Ray, that front end looks super clean! No dirt, crud, or excess grease - just a little rust.

I'd be ashamed to share a pic of my Astro with the front wheel off!  :-\

Thanks George! -- It's a clean car and has relatively low mileage. I love the old wide body platform, and I absolutely LOVE the later year Northstar 4.6L V8. DOHC and chain driven makes for a stout top end and overall motor integrity. To me a Caddy must have a V8, otherwise it's not a Caddy -- LOL

I know I'm living in the past, but for my old a$$ and long road trip driving comfort, this thing rocks. GM knew the demographic that they were building this car for  -- old guys like me. Mrs. GF was at first skeptical, but she's come around to the comfort and smoothness of the ride.

Best of all -- It's not too computerized and techno-laden so that I can still fix it myself.
« Last Edit: September 17, 2019, 09:53:44 AM by goodfellow »

Offline fatfillup

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #7 on: September 17, 2019, 04:50:18 PM »
What year is that Caddy.

And I agree on the V8.

I also appreciate a luxury ride, loved my Town cars.

Online goodfellow

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #8 on: September 17, 2019, 05:11:21 PM »
What year is that Caddy.

And I agree on the V8.

I also appreciate a luxury ride, loved my Town cars.

2011 --

Offline Uncle Buck

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #9 on: September 18, 2019, 06:38:24 PM »
What year is that Caddy.

And I agree on the V8.

I also appreciate a luxury ride, loved my Town cars.

Panther platform Ford/Lincoln/Mercury, I love them. I would love to get an Interceptor. You have not lived until you drive a retired cop car Crown Vic. Oh my the feeling of putting her to the wood, then the feeling when you stand on the brakes. Nothing like it. Those ol retired cop cars really do haul ass!  >:D
You boys better hold on cause I'm gonna have to stand on it!

Offline slip knot

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #10 on: September 18, 2019, 09:40:23 PM »
The PPV are getting hard to find now. The hot rod crowd figured out they got good engine drive train combos and the price reflects that now

Online goodfellow

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #11 on: September 27, 2019, 12:37:02 PM »
Interesting phenomenon! -- This last go-round with the Caddy had me a little paranoid, and to be honest; worried. Last week Mrs Gf and I took a long road-trip out of state visiting friends. Over dinner the conversation wound up on this topic because we used the Caddy to make the drive. In the middle of the conversation Mrs. GF noted that she "thinks" she hears a scraping noise in the front of her car (2012 Traverse). I took note because a few months ago I replaced the front and rear brakes on her car using the CRC caliper grease.

Today I took it for a ride -- sure enough, the front is dragging and making noise. I put it on the lift and took the pads out and the slide pins were indeed sticky. The left (driver's side) more so than the right. I cleaned every bit of the CRC grease out and lubed with Sil-Glyde, but I think the damage to the bushings is done. A new AC/Delco bushing and slide pin boot kit is on order ($7.89) from Amazon, and will be installed next week.

Glad Mrs. GF was paying attention and alerted to the fact that she might have a problem. After almost 40 years putting up with a "gear head", some of it may actually be "rubbing off" on her. === LOL
« Last Edit: September 27, 2019, 12:41:52 PM by goodfellow »

Offline stokester

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #12 on: September 27, 2019, 12:53:08 PM »
The PPV are getting hard to find now. The hot rod crowd figured out they got good engine drive train combos and the price reflects that now
Having worked on a number of Chevrolet Caprice PPVs, made by Holden, with the 6.0 and great brakes I wonder if those are also in demand.
Nick
Yorktown, VA

Offline kwoswalt99

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #13 on: September 27, 2019, 12:57:34 PM »
What year is that Caddy.

And I agree on the V8.

I also appreciate a luxury ride, loved my Town cars.

Panther platform Ford/Lincoln/Mercury, I love them. I would love to get an Interceptor. You have not lived until you drive a retired cop car Crown Vic. Oh my the feeling of putting her to the wood, then the feeling when you stand on the brakes. Nothing like it. Those ol retired cop cars really do haul ass!  >:D

0-60 by next year!

Offline stokester

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #14 on: September 27, 2019, 02:10:01 PM »
Glad Mrs. GF was paying attention and alerted to the fact that she might have a problem. After almost 40 years putting up with a "gear head", some of it may actually be "rubbing off" on her. === LOL
My better-half and both daughters don't hesitate to ask me about a noise or feel although they also know the questions I will ask. 
Nick
Yorktown, VA

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #15 on: September 28, 2019, 03:04:14 PM »
I usually don't post anything from the other "channel", but this post directly relates to the brake lube problem. Same issues are discussed.

https://www.garagejournal.com/forum/showthread.php?t=432027

Offline stokester

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #16 on: September 28, 2019, 06:01:01 PM »
I usually don't post anything from the other "channel", but this post directly relates to the brake lube problem. Same issues are discussed.

https://www.garagejournal.com/forum/showthread.php?t=432027
I blame both the OEM and lubricant manufacturers for not being open about the composition of the components or any compatibility issues.  This leads to what we see here.

There is no universal answer here but I have found that using a silicone grease or lubricant on rubber or plastic components prevents problems.  When replacing the rubber seals on my air-cooled VW bugs there were many who recommend using dishwashing liquid or similar soap-based compound for lubricant.  I found that a simple spray with silicone lube would last longer and not get sticky as it dried.
Nick
Yorktown, VA

Offline ron350

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #17 on: September 28, 2019, 07:44:36 PM »


That guy used Super Lube Synthetic Grease #21030 made for ratchets etc. not for brake rubber.


Online goodfellow

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #18 on: September 28, 2019, 08:37:19 PM »
I will report back on the Sil-Glyde product. I would guess that even plain old silicone di-electric grease would suffice to keep the rubber from deteriorating, but i don't know what extreme heat and cold would do to the viscosity.

Offline stokester

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #19 on: September 29, 2019, 07:13:52 AM »
I will report back on the Sil-Glyde product. I would guess that even plain old silicone di-electric grease would suffice to keep the rubber from deteriorating, but i don't know what extreme heat and cold would do to the viscosity.
That is what GM recommends for door and T-top seals.
Nick
Yorktown, VA

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #20 on: December 11, 2019, 03:46:41 PM »
Well it's been 2-1/2 months since I had these issues with the grease and the boots/seals. I'm quite happy to report that the noise due to boot and seal problems have not returned in both the Caddy and the Traverse. The Sil-Glyde seems to do the trick on this application. 

Offline bonneyman

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Re: Cadillac DTS front brakes sticking and worn strut bearing -
« Reply #21 on: December 11, 2019, 09:01:11 PM »
Yeah, one has to be careful with polymer compatibility everywhere these days. (The HVAC industry is a real can o worms!)
I remember when I had the Toyota I would add marvel Mystery Oil to the gas tank to help lube the upper end on the new motor. Must have added a bit too much, as the auxillary accelerator pump on the carb had the diaphram dissolve and flood the thing with gas till the engine warmed up. Then fine. Seems the solvents in the MMO don't like new rubber parts.