4g61t.org
http://4g61t.org/forum/

Need Confirmation on Brake Rotor Diameter
http://4g61t.org/forum/viewtopic.php?f=17&t=38750		 Page 1 of 1
Author:  ctwombly [ Wed Apr 16, 2014 10:26 pm ]
Post subject:  Need Confirmation on Brake Rotor Diameter
Purchased stock brake rotors for my 90 Colt GL from Advance Auto. I stacked them up against the rotors I pulled off the Colt and they were slightly larger in diameter. A rough measure with a tape measure has the old rotors at 9.125" and the new rotors at 9.5". Perhaps the old ones are slightly worn down from age and rust around the edges, but that still seems like a significant difference to me. I don't want to put the captive rotor together to find the brake caliper won't mount correctly due to the incorrect rotor.

On page 2 of the Colt Turbo FSM provided by lilevo, there is a reference for rotor diameter of 9.6" under the 1500 column (must be a reference for both the turbo and na models) so hopefully this is a positive indication that these rotors will work with my application. Here is the link:

http://www.lilevo.com/mirage/89%20Colt% ... arking.pdf

Any confirmation or comments are appreciated. Thanks in advance!
Author:  Flying Eagle [ Thu Apr 17, 2014 9:14 pm ]
Post subject:  Re: Need Confirmation on Brake Rotor Diameter
The FSM is prone to typos. Very prone.



ASA lists the following for low and economical lines of the C52a base model, solid front rotor brake setup:

1988.04.1 to 1990.05.3 MB366435 Superceded to MB316676 13" (I suspect that is in fact 13mm thickness solid)
1990.06.1 to 1992.04.3 MB618737 Superceded to MB618736 13" (same thing about rotor thickness, non-vented style, captive)

I always thought the stock brakes were in the 238mm diameter range, but that is the MI238 number that sticks in my head for rotors from Brembo.

Here are listings from Ferodo and Brembo from 1990.06.1 listed with Rockauto:

FERODO Part # DDF947 {#MB618736, MB618737} Diameter [mm]: 234; Brake Disc Thickness [mm]: 13; Minimum Thickness [mm]: 11.4; Centering Diameter [mm]: 86; Number of Holes: 4; Height [mm]: 34; Sold In Pairs
Flag indicates this part fits vehicles sold in the European Market. It does not indicate where the part was made -- manufacturers produce parts in multiple factories worldwide. Front Axle

BREMBO Part # 08707210 {#25198, MB618737}
Flag indicates this part fits vehicles sold in the European Market. It does not indicate where the part was made -- manufacturers produce parts in multiple factories worldwide. Front; solid disc; 05/90 on [Wholesaler Closeout -- 30 Day Warranty] (Only 12 Remaining)

Not sure if the site is wholy accurate or not, but multiple listings for the same Mitsu number and same rotor diameter.

Whatever rotor you get, it has to match the exact diameter of the old rotor. Place the rotors back to back, contact surface to hat, hat to contact surface to confirm the offset of the hat is identical too. I see cheap white box parts and I've seen some serious alignment and fitment issues. If your rotor barely clears now, what happens when it rusts? :wink:
Author:  ctwombly [ Sat Apr 19, 2014 12:40 am ]
Post subject:  Re: Need Confirmation on Brake Rotor Diameter
Quote:
Whatever rotor you get, it has to match the exact diameter of the old rotor. Place the rotors back to back, contact surface to hat, hat to contact surface to confirm the offset of the hat is identical too. I see cheap white box parts and I've seen some serious alignment and fitment issues. If your rotor barely clears now, what happens when it rusts? :wink:
Absolutely, and couldn't agree with you more. Precisely the reason for my concern. The first thing I did was mate them back-to-back and noticed the new rotors were slightly larger. The measurement showed this to be true. It appears that I have rotors that would fit the "1500" vehicle listing in the FSM, which states 9.6".

I will say, the measurements listed from RockAuto seem to match up with the old rotor so I'll have to cross-reference that and see if Advance carries a compatible rotor. Thanks for posting that as it should help me get the correct part. Much appreciated!
Author:  89Mirageman [ Sat Apr 19, 2014 8:22 am ]
Post subject:  Re: Need Confirmation on Brake Rotor Diameter
Aren't the rotors for the sedan and the hatch slightly different? This is for both the NA versions I mean. Maybe they gave you sedan rotors.
Author:  ctwombly [ Sat Apr 19, 2014 9:39 am ]
Post subject:  Re: Need Confirmation on Brake Rotor Diameter
That could be the issue, I just don't know for sure. Here is what they sold me:

http://shop.advanceautoparts.com/p/wear ... fragment-2

There description for vehicle matches mine, but looking at the specifications, the rotor diameter is 243mm whereas I need the 234mm diameter rotor that Flying Eagle linked. I will search through different Colt models on the Advance website to see if I can find some to exchange with. They have several listings for Colt models, which probably don't completely match up with the real world models/parts.
Author:  ctwombly [ Sat Apr 19, 2014 10:22 am ]
Post subject:  Re: Need Confirmation on Brake Rotor Diameter
Posting this as a follow up in case anyone else has an issue with Advance Auto in the future. I spoke with an online rep and had him cross reference some of the parts Flying Eagle provided. He ended up with the following Wearever brake rotor for the front:

http://shop.advanceautoparts.com/p/wear ... 15890222-P

This is the smaller 234mm rotor that I need for my 1990 Colt GL hatchback that originally came with the 4g15 engine, instead of the 243mm rotor that I kept finding for various models of 3g CSMs. All other dimensions match up so this should solve my problem.

Thanks again gents for providing feedback to help me resolve this.

P.S. Use Advance online and issue the code TRT30 for 30% off. It's been a long-lasting code that they don't advertise. I usually order online and pick up at my closest physical location about 5 miles away.
Page 1 of 1 All times are UTC-05:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/