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Discussion Starter · #1 ·
Ok, so I have used the search function, but wading through the various threads and reading contradictory responses, I'm just looking for a quick response.

NAPA lists the Impala SS and 9c1 calipers as the same part number - is this correct?

Reason I ask is I have a '92 civilian car, and I ordered new cross drilled/slotted rotors and pads for a ficticious '95 Impala SS.

I wish to purchase reman calipers and just need to confirm whether to order the '92 civi calipers or the SS calipers/9c1 calipers.

I believe the answer is SS/9C1 calipers but I need a voice of wisdom.

Discussion Starter · #2 ·
The question is, what year 9C1 is the NAPA listing for?

All 91-96 cars used calipers that were common with the exception of the RPO JA9 spec front brakes.

The 94-96 police front caliper IS different--wider casting. It is the only use of JA9 specs on the late B-body, though the wider calipers were also used on 1A2 wagon and 9C6 taxi packages.

One of many posts in Forum addrssing this in some way:;f=23;t=000244

SEARCH Brake Forum using "JA9" 36 posts, lots of info

Discussion Starter · #4 ·
Nick, I have to assume that the data in the NAPA base is flawed, or they've decided to eliminate some of the inventory complications and offer only one spec.

You can see that the SS & 9C1 are different, at least as originally produced by GM.

Would you be able to post the PN info you have so I can look at the NAPA US data, in case it's different?

Discussion Starter · #5 ·
NAPA part number SDC 2422204 caliper (left front, semi loaded) shown for both '95 Impala SS and '95 Caprice Police car or Taxi.

Coincidentally the two cars also share the same part number for the reman master cylinder P/N TS 102683. They do list a different part number for the disc/drum caprice.

They still list a second part number for the non police/taxi/Impala ss for calipers, so I don't see it being likely that they've done this to simplify stock.

Bottom line - if I have SS pads, do I want the standard calipers and not 9c1 spec?

Discussion Starter · #6 ·
Nick, I know there is not total agreement as I'm expressing it. A number of B-body owners do mix the 9C1 caliper and SS pads. I still believe it is BEST to use what was intended for the RPO specs.

There is one possible fly in the ointment--I am fairly certain the 92 car, unless parts have been changed, uses a different knuckle than the WX3 (SS) and 7B3 (9C1) cars built in 94-96. The casting shape MAY interfere with using the later calipers--but as I think about this, the answer is more likely that a "correct" caliper for any 91-96 will work with no clearance grinding.

I don't know what latitude you may have as far as the supplier, or if you are budget-limited, but since you are replacing the calipers and rotors, I'd use the 9C1 spec calipers and the correct pads. I read your posts as indicating you have already gotten the pads (for an SS) and may have no choice as far as using them rather than returning or exchanging them.

If possible, I'd swap to the 9C1 pads and get the corresponding calipers.

My reasoning is that should you decide to go with the 9C1 calipers and the (thinner) SS pads, you're starting out with the piston further out of the caliper bore. Since you live in Canada (though I don't know if the weather in Alberta gets "that" nasty), the additional pistong/seal exposure could lead to eventual/early problems in the replacement calipers, depending on the mix of parts and operating environment.

Discussion Starter · #7 ·
Thanks for the input Bill.

The car has Belltech spindles, which cover '91-'96 so I think we can rule out a difference in the casting between years being an issue.

I think based on your input I will just go for the standard caliper and not bother with the 9c1 units. I have the SS pads and I don't have any use for the extended service intervals of the 9c1 parts.

The car is not winter driven, it's a show car that sees about 5k miles a year give or take and is stored 3/4 of the year.

So being that you're a very knowledgeable guy Bill, I'll take your word for it that the SS calipers are the same as a standard caprice caliper and just go with that.

Am I correct with that statement? If thats true NAPA must be mistaken with their listings.

Discussion Starter · #8 ·

From a generic standpoint, the Impala SS caliper casting is essentially the same as other 91-96 B-body calipers, with the exception of the 9C1 caliper, which IS wider. There are other minor differences, but considering your use of an aftermarket knuckle, I cannot say with certainty that a specific caliper will or will not work--I have no experience with lowering knuckles, and don't know if the manufacturer provides any specific requirements for caliper fit.

As far as how the aftermarket/remanufacturer sector identifies the various applications, I suspect it comes down to which pads are loaded into the caliper that determines it's intended application. GM did no one a favor here, as there are several pads that fit the same caliper, and it does become confusing at the parts store identification level. I won't go so far as to say that NAPA has erroneous information--it's too simplistic to say that without alot more research, and I'm not going to be concerned until or unless I start using their stuff and encounter a problem in the process.

The 9C1 thicker pad setup isn't just about longer change intervals--it's to improve overall brake performance in a heat-soak situation. Your show car should be fine with the "regular" stuff.
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