Author Topic: front calipers, is there options with piston size? (Read 1815 times)

brads70 · « **on:** March 06, 2010 - 01:38:32 PM »

Just wondering before I order some calipers if there are different piston diameters for calipers? From different years, models etc....?

If there is a choice ,any recomondations?
I have pin style now with 11 3/4 rotors, manual master.

72bluNblu · « **Reply #1 on:** March 06, 2010 - 02:31:23 PM »

For the stock pin type 11 3/4" caliper brackets I believe they're all the same piston diameter. The earlier 4 piston KH calipers are obviously different, but they use a different bracket too.

Bullitt- · « **Reply #2 on:** March 06, 2010 - 03:29:35 PM »

Brad I thought you were a DIY guy... Unless there is something really wrong with your calipers that you would need to exchange them they can be rebuilt for just a few dolla .

Caliper Seal Boot Kit - Front
Product Line: NAPA ULTRA PREMIUM BRAKE PARTS
Part Number:       UP 520
Price:
Price
Unit
    :
:
   3.69
Each
Features & Benefits       Designed To Match O.E. Fit, Form & Function.; Rubber Components Meet SAE Specifications For Durability & Performance.; Compatible w/ DOT Approved Silicone- Or Glycol-Based Brake Fluids.; High Quality Rubber Ensures Trouble-Free Operation.
Warranty       Limited Lifetime-See Manufacturers Written Policy
Warranty PDF

Material Safety Data Sheet       There is no MSDS for this item
Application Information:       1970 Dodge Challenger
Per Car Qty: 2
http://www.napaonline.com/Search/Detail.aspx?A=UBP520_0067223415&An=599001+101970+50020+2020006

brads70 · « **Reply #3 on:** March 06, 2010 - 04:46:14 PM »

Thanks Wade!
It's just they are $18 bucks I think for new/rebuilt no rust etc.., so I was wanting to paint them and mine are a bit rusty, so it's not worth the effort to me, to rebuild them.
I was just wondering if there was different size pistons to chose from before I ordered.
Thanks also, 72bluNblu I didn't think or haven't heard of any other sizes, just wanted to be sure.

Katfish · « **Reply #4 on:** March 06, 2010 - 04:57:31 PM »

There are definitely different sizes, I used a caliper from a 77 Charger, bigger than what was used on the E & A bodies.

brads70 · « **Reply #5 on:** March 06, 2010 - 05:01:50 PM »

Quote from: Katfish on March 06, 2010 - 04:57:31 PM

There are definitely different sizes, I used a caliper from a 77 Charger, bigger than what was used on the E & A bodies.

Ahh... there ya go, learned something new! Are yours pin or slider type?

Katfish · « **Reply #6 on:** March 06, 2010 - 05:03:30 PM »

I have sliders, you might want to check the size thing at Rockauto, I thought they may be different. But it's been awhile, not 100% sure.

Katfish · « **Reply #7 on:** March 06, 2010 - 05:32:40 PM »

From ebooger's how to:

"There are other ways to alter front/rear balance. One way, which reduces rear lockup, is to use a 7/8-inch rear wheel cylinder in place of the standard 15/16-inch unit. Try Raybestos part number WC37236 for this. (Original application: late �70-early �80s light-duty Dodge trucks w/10-in. rear drums).

The second variable is caliper piston size. The slider-type calipers used on 1973-�75 A-bodies used a smaller piston: 2.60" as opposed to the more common 2.75". Using these can be helpful if your car has a �reverse� proportioning problem and tends to lock the fronts first, usually only a problem with no-option, slant-six cars or lightened drag cars."

brads70 · « **Reply #8 on:** March 06, 2010 - 05:36:37 PM »

Ya I just learned about the rear wheel cylinders last week, I'm going that route.
Thanks! Gotta love this site!

PS, who is ebooger? LOL

72bluNblu · « **Reply #9 on:** March 06, 2010 - 05:49:55 PM »

Learn something new every day! I knew about the wheel cylinders, but not about the 2.6" pistons on the a body sliders. Although, I'm not really sure why you would want to go to a smaller piston if you have the 2.75's already. More of a 'make sure you don't accidentally get the smaller ones' kind of thing.

HP2 · « **Reply #10 on:** March 06, 2010 - 06:53:01 PM »

Changing out piston/cylinder sizes will also alter fluid displacement and pedal pressure and travel. Doing so could create situations where the pedal ratio on your set up creates really touchy brakes or extreme amounts of travel without adequate braking pressure.

If your going bigger, you will need a master cylinder than displaces more fluid to maintain the same pedal pressure and clamping force. Going smaller would create the opposite situation where pedal travel would create greater pressure at the calipers.

brads70 · « **Reply #11 on:** March 06, 2010 - 07:00:33 PM »

Ya I'll just order stock replacement pin type calipers and the 7/8 rear brake cylinders

Bullitt- · « **Reply #12 on:** March 06, 2010 - 07:20:56 PM »

Late 80s Pickups use a 3.1" piston..caliper looks similar to the late 70's slider

shadango · « **Reply #13 on:** March 07, 2010 - 01:14:46 AM »

I just installed the truck rear brake cylinders mentioned above and sliders from an 80 NYer in the front, along with the newer style aluminum MC (has the same bore as the original MC).....

I didnt measure the piston on the calipers I am using but they look huge.

Initial pedal travel/feel during bleeding feels good so far but havent had the car out yet....hopefully later today. crossing fingers.

autoxcuda · « **Reply #14 on:** March 07, 2010 - 04:58:36 AM »

Quote from: brads70 on March 06, 2010 - 01:38:32 PM

Just wondering before I order some calipers if there are different piston diameters for calipers? From different years, models etc....? If there is a choice ,any recomondations?
I have pin style now with 11 3/4 rotors, manual master.

Are you going to plumb in a adjustable proportioning valve? That will help you dial in the proportioning.

Author Topic: front calipers, is there options with piston size? (Read 1815 times)

brads70

front calipers, is there options with piston size?

72bluNblu

Re: front calipers, is there options with piston size?

Bullitt-

Re: front calipers, is there options with piston size?

brads70

Re: front calipers, is there options with piston size?

Katfish

Re: front calipers, is there options with piston size?

brads70

Re: front calipers, is there options with piston size?

Katfish

Re: front calipers, is there options with piston size?

Katfish

Re: front calipers, is there options with piston size?

brads70

Re: front calipers, is there options with piston size?

72bluNblu

Re: front calipers, is there options with piston size?

HP2

Re: front calipers, is there options with piston size?

brads70

Re: front calipers, is there options with piston size?

Bullitt-

Re: front calipers, is there options with piston size?

shadango

Re: front calipers, is there options with piston size?

autoxcuda

Re: front calipers, is there options with piston size?