86 SILVERADO what discs do I need? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ozkiwi · 03-27-2013, 09:20 PM

The supplier cant tell which one I need to replace the worn front rotors on my truck.part no 5006 which are 11 7/8th
or 5032 which are 11 41/64.
Truck is not here so can't measure.
Also rear wheel cylinder either 2 inch or 2 3/4.
Can any one help ?

Vin:2gcec14h2g1170202

Keith Seymore · 03-28-2013, 08:07 AM

Yes -

Here is the brake system release chart for an '87 ('86 should be the same).

Scan through there and see what you find.

Your truck would be the equivalent of an R10, and I believe you'll find front rotors are 11.86" (probably what they are calling 11 7/8 = 11.875).

Additionally, you said "rear wheel cylinders" but your choices do not make sense. I think you meant the width of the rear brake shoes, which you will find to be 2.75".

K

silvereagle07 · 03-28-2013, 10:01 AM

Measure the thickness of the rotor. It will be 1" or 1.25". Then measure the depth of the drum. It will be 2" or 2.75".
Posted via Mobile Device

Keith Seymore · 03-28-2013, 10:31 AM

Quote:

Originally Posted by silvereagle07

Measure the thickness of the rotor. It will be 1" or 1.25". Then measure the depth of the drum. It will be 2" or 2.75".

Quote:

Originally Posted by ozkiwi

Truck is not here so can't measure.

You probably missed that detail by being on your phone.

Can you see the chart? It's what we used in order to release the parts to production.

K

silvereagle07 · 03-28-2013, 12:21 PM

Sorry Keith. I missed original info on the tiny phone screen.

Keith Seymore · 03-28-2013, 12:30 PM

Quote:

Originally Posted by silvereagle07

Sorry Keith. I missed original info on the tiny phone screen.

Thought so.

What do you wanna bet Ozkiwi is sleeping right now? He'll probably see this when he gets up in a few hours....

(lol)

K

ozkiwi · 04-02-2013, 04:00 AM

The brake option is J55 is that the same as JB5 ?

silvereagle07 · 04-02-2013, 07:46 AM

J55 brakes use the same rear shoes as JB5 / JD5 (11 5/32" x 2 3/4").
J55 indicates it has the HD brake system. I googled the GM RPO codes and found these pages. http://www.marshu.com/images-website...-car-codes.pdf

Keith Seymore · 04-02-2013, 09:27 AM

Quote:

Originally Posted by ozkiwi

The brake option is J55 is that the same as JB5 ?

Yes.

K

Keith Seymore · 04-02-2013, 09:29 AM

Quote:

Originally Posted by silvereagle07

I googled the GM RPO codes and found these pages. http://www.marshu.com/images-website...-car-codes.pdf

Be careful - RPO codes can change and/or be re-used over the course of the model years. It's best if you can find RPO information specific to trucks and ideally for the model year of interest.

K

03-27-2013, 09:20 PM	#1
ozkiwi Registered User Join Date: Nov 2012 Location: melbourne australia Posts: 196	86 SILVERADO what discs do I need? The supplier cant tell which one I need to replace the worn front rotors on my truck.part no 5006 which are 11 7/8th or 5032 which are 11 41/64. Truck is not here so can't measure. Also rear wheel cylinder either 2 inch or 2 3/4. Can any one help ? Vin:2gcec14h2g1170202

03-28-2013, 08:07 AM	#2
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,175	Re: 86 SILVERADO what discs do I need? Yes - Here is the brake system release chart for an '87 ('86 should be the same). Scan through there and see what you find. Your truck would be the equivalent of an R10, and I believe you'll find front rotors are 11.86" (probably what they are calling 11 7/8 = 11.875). Additionally, you said "rear wheel cylinders" but your choices do not make sense. I think you meant the width of the rear brake shoes, which you will find to be 2.75". K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ Last edited by Keith Seymore; 03-28-2013 at 08:14 AM.

03-28-2013, 10:01 AM	#3
silvereagle07 Registered User Join Date: Sep 2008 Location: Bailey, NC Posts: 2,462	Re: 86 SILVERADO what discs do I need? Measure the thickness of the rotor. It will be 1" or 1.25". Then measure the depth of the drum. It will be 2" or 2.75". Posted via Mobile Device __________________ Jeramy '84 GMC project truck '85 Chevy 4X4 SOLD '07 Chevy Trailblazer SS 5th Annual SHPHC Car/Truck Show Pics http://67-72chevytrucks.com/vboard/s...d.php?t=543605 UPDATED PICS! CHECK 'EM OUT

03-28-2013, 12:21 PM	#5
silvereagle07 Registered User Join Date: Sep 2008 Location: Bailey, NC Posts: 2,462	Re: 86 SILVERADO what discs do I need? Sorry Keith. I missed original info on the tiny phone screen. __________________ Jeramy '84 GMC project truck '85 Chevy 4X4 SOLD '07 Chevy Trailblazer SS 5th Annual SHPHC Car/Truck Show Pics http://67-72chevytrucks.com/vboard/s...d.php?t=543605 UPDATED PICS! CHECK 'EM OUT

04-02-2013, 04:00 AM	#7
ozkiwi Registered User Join Date: Nov 2012 Location: melbourne australia Posts: 196	Re: 86 SILVERADO what discs do I need? The brake option is J55 is that the same as JB5 ?

04-02-2013, 07:46 AM	#8
silvereagle07 Registered User Join Date: Sep 2008 Location: Bailey, NC Posts: 2,462	Re: 86 SILVERADO what discs do I need? J55 brakes use the same rear shoes as JB5 / JD5 (11 5/32" x 2 3/4"). J55 indicates it has the HD brake system. I googled the GM RPO codes and found these pages. http://www.marshu.com/images-website...-car-codes.pdf __________________ Jeramy '84 GMC project truck '85 Chevy 4X4 SOLD '07 Chevy Trailblazer SS 5th Annual SHPHC Car/Truck Show Pics http://67-72chevytrucks.com/vboard/s...d.php?t=543605 UPDATED PICS! CHECK 'EM OUT



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