Heads-up On Disc Brake Calipers

[sdsaw]

Here's a little heads up for anyone with disc brakes on their trailer that needs new brake pads.
Instead of just retracting the caliper piston back in, I just found out that you should pop the piston out to check for rust / corrosion.
It seems as a new piston extends out as the pads wear, the exposed surfaces may start to rust. Not a problem until you push the corroded surfaces back into the caliper.
I didn't notice any leakage, but the brakes started dragging because the piston started to seize in the caliper bore.

These are 4 yrs. old used in the saltwater and always rinsed after launching and retrieving the boat.
My trailer guy tells me a 2 yr. life-span is not uncommon.
Yeah, you'll have to bleed your brakes, but it will avoid braking issues down the road.

UFP DB-42 Calipers, 12" vented rotors

Scott

 

[Shizzy]

Re: Heads-up On Disc Brake Calipers

Wow!

 

[donnymac]

Re: Heads-up On Disc Brake Calipers

WOW! X2 and thanks.

 

[redfury]

Re: Heads-up On Disc Brake Calipers

Seems like a failed seal was at fault more than anything...don't those brakes have a rubber seal that extends with them as they are pushed out like a conventional automotive system?

I'd agree though, it's certainly not a bad idea to go through the system thoroughly and assume nothing when it comes to brakes. I've had 2 calipers drag on me because I assumed they'd be fine on my two vehicles. One got new calipers, the other is probably going to get some soon.

 

[sdsaw]

Re: Heads-up On Disc Brake Calipers

Seems like a failed seal was at fault more than anything...don't those brakes have a rubber seal that extends with them as they are pushed out like a conventional automotive system?

I'd agree though, it's certainly not a bad idea to go through the system thoroughly and assume nothing when it comes to brakes. I've had 2 calipers drag on me because I assumed they'd be fine on my two vehicles. One got new calipers, the other is probably going to get some soon.

Yes, they do have a rubber dust seal. It slips into the groove on the piston and is connected to the caliper.
The sealing takes place approx. 3/8" below the groove. The section that's not as corroded was inside the bore of the caliper.
In the first picture, the piston on the left was the culprit, causing the brakes to drag (rust made the diameter too large).
Don't assume anything...
Check your pistons too! Especially if you're in the saltwater

Scott

 

[bruceb58]

Re: Heads-up On Disc Brake Calipers

I saw your replacement pistons on the Saltwater fishing board....nice work!

http://www.allcoast.com/discussion/ViewTopic.cfm?topic_ID=90427

 

[redfury]

Re: Heads-up On Disc Brake Calipers

was the seal on the piston on the left damaged? That's a lot of corrosion for a supposedly well sealing caliper boot.

 

[franco802]

Re: Heads-up On Disc Brake Calipers

Wow, thanks for the heads up!!!!

 

[sdsaw]

Re: Heads-up On Disc Brake Calipers

was the seal on the piston on the left damaged? That's a lot of corrosion for a supposedly well sealing caliper boot.

The seal is a square o-ring and very tough. Didn't notice any damage or leakage of brake fluid.
I think that the boot is for brake dust protection. I don't believe that they are 100% water tight.
I feel that there won't be any problems until you install new pads and have to push the piston back in.

Scott

 

[dingbat]

Re: Heads-up On Disc Brake Calipers

I'd ditch those the next time around and go with a pair of Kodiak disc with Stainless steel pistons. Even the el-cheapo Tiedowns I used before don't have that problem.

 

[sdsaw]

Re: Heads-up On Disc Brake Calipers

I'd ditch those the next time around and go with a pair of Kodiak disc with Stainless steel pistons. Even the el-cheapo Tiedowns I used before don't have that problem.

They will eventually.
Even the stainless ones!
These have four years of saltwater use.
Stainless is rust resistant, but not rust proof.

 

[Stachi]

Re: Heads-up On Disc Brake Calipers

The seal is a square o-ring and very tough. Didn't notice any damage or leakage of brake fluid.
I think that the boot is for brake dust protection. I don't believe that they are 100% water tight.
I feel that there won't be any problems until you install new pads and have to push the piston back in.

Scott

salt and rubber are no happy marriage...this happens on cars as well...