1. Home
  2. Automotive Technologies
  3. Backing Plate Question

Backing Plate Question

One of the main goals during this '88 Civic restoration, was not only to remove as much existing rust as possible but try to prevent it from returning. One theory is to take things like the controls arms, strip the loose rust and wire brush the rest, apply a rust primer to any bare metal, then some rust paint, and finally some undercoat. It's overkill I know, I mean who else undercoats both sides of a fuel tank, but I believe in doing a very thorough job. My question however concerns one of the brake backing plates. The other plate was rusted beyond saving, so it is on the list of parts to be replaced. The other had a lot of surface rust but was still intact, with no holes or weak spots. So after cleaning it up, I applied primer and paint to both sides. I haven't got as far as reinstalling this plate yet, but a thought since occured to me: was there a reason the inside of this plate wasn't coated in the first place? I'm wondering if over time, this paint could flake off and end up contaminating the braking surfaces. Does this mean I have to strip the plate down again, or am I worrying too much?

Reply to
Chris F.
Loading thread data ...

Personally I think undercoat sucks. I wouldn't use it at all.

That said, the inside of the brake is not undercoated because of the high temps that are experienced, you don't want warm tar dripping onto your braking surfaces, that will make the brakes grabby and/or less efficient. Paint only inside the brakes, period. There's no issue with using paint, my '55 Stude had painted backing plates from the factory and the brakes have been working fine for 54 years. Of course I repainted them when I redid the brakes and suspension.

nate

Reply to
Nate Nagel

"Chris F." wrote in news:49f34d7e$0$5483$ snipped-for-privacy@news.aliant.net:

It was originally painted black on both sides. The original paint was not high-gloss, but had a bit of a satin finish.

You're worrying needlessly. Just paint it and be happy.

If I were you, I'd wait for the new plate to come in so you can match your new paint to that. Some barbecue paints have about the right type of sheen to work well in this application. Krylon, for instance.

Reply to
Tegger

Well, better safe than sorry. I'd rather ask a stupid question now than receive a nasty surprise later.

I used a light shade of gray - nobody's going to see it behind the wheel and brake drum anyway. Gray is handy on the other parts, because it makes it easier to see where the rubber coat has been applied (or may need reapplication later).

Reply to
Chris F.

"Chris F." wrote in news:49f39436$0$5486$ snipped-for-privacy@news.aliant.net:

Oh, this is for the DRUM. I thought you meant the DISC backing plate. Those are a lot thinner than the drum backers and rust out faster.

In the case of the drum backing plate you'd have been better off to simply leave the inner face unpainted, and just put proper grease on the contact points.

No harm done if you /have/ painted it, though...

Reply to
Tegger

On these cars, those are called splashguards. Correct me if I'm wrong, but doesn't a backing plate - by definition - have to transfer energy during the braking process?

Reply to
Chris F.

"Chris F." wrote in news:49f63fa3$0$5460$ snipped-for-privacy@news.aliant.net:

The Honda service manual calls it a "backing plate" on the rear drums, and a "splash guard" on the front discs.

I got lazy calling the disc brake part a "backing plate".

Reply to
Tegger

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.