Couple questions I have regarding my future brake upgrade. I have an '86 GT with an '88 rear suspension/brake setup. I would like to upgrade the front rotors to vented discs. I don't want to increase weight that much, and since my car already stops pretty good (I have done quite a bit of lightening) I don't want to spend a ton of money on huge brakes. I had settled on doing the Grand Am front conversion. I already know this will add 6 pounds of weight per side. My first question is; are there any options for lightweight grand am calipers? The second is regarding brake balance; will the grand am front/'88 rear combo retain a good front/rear balance? I am told the grand am piston is larger. Is the '88 caliper piston larger then the 84-87? Will this give me too much front brakeing power?
I can't answer the lightweight GA option question you have, but I can answer the balance question. I have the GA brakes on the front of my 308 kit and the stock Fiero '84 - '87 brakes on the rear. I find that the brake balance didn't change noticeably when I did the change-over. I would assume by upgrading to the GA's on your car, you will actually restore some of the original balance that was lost when the '88 rears were installed.
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08:22 AM
82-T/A [At Work] Member
Posts: 25005 From: Florida USA Registered: Aug 2002
Couple questions I have regarding my future brake upgrade. I have an '86 GT with an '88 rear suspension/brake setup. I would like to upgrade the front rotors to vented discs. I don't want to increase weight that much, and since my car already stops pretty good (I have done quite a bit of lightening) I don't want to spend a ton of money on huge brakes. I had settled on doing the Grand Am front conversion. I already know this will add 6 pounds of weight per side. My first question is; are there any options for lightweight grand am calipers? The second is regarding brake balance; will the grand am front/'88 rear combo retain a good front/rear balance? I am told the grand am piston is larger. Is the '88 caliper piston larger then the 84-87? Will this give me too much front brakeing power?
Wow, is it really 6 pounds?
Here is a before / after comparison if you want to see the difference in size, etc...
as to the balance - I have the Grand Am up front, and stock rears - and the front braking is way to much. and, it is NOT due to my rears being old/out of shape. I am in the process of putting on the Cadillac Seville brakes on the rear to make for a better balance. By the math per the cyl bores - it should be back to near stock for balance. Just waiting for decent weather outside to make it happen. got the Seville calipers from the you-pull-it, and got rebuild & hardware kits for them. sanded them smooth & painted them. the brackets weere made by DPwood (I think? ArnsGT knows more).
The 88 Fiero has much better brakes than the 84 to 87 If you use the Grand am brakes on the front there is a substantial weight increase because you add steel calipers and extra weight from the 2nd rotor,,I have not read any post saying this affected handling . ..If possible you should try to install 88 Fiero brakes on the front also.. ..You can install Wagner thermoquiets pads to your stock front 86 calipers ,I think you will be satisfied with the rear 88 brakes and the stock 86 calipers loaded with thermoquiets , this should give you a more balanced braking.. the front brake hoses should be replaced .I have braided steel hose I got from blacktree,on the front.but stock new hose will do the job ..this past week end I installed Grand Am brakes on the rear of my 86GT the rear now chirps the rear tires if I hit the brakes hard,,on the rear I installed low end pads,paid $5.95 on a rock auto close out(Yes Im frugal) I have not yet installed the front thermoquiets ,I have a Quality mid level pad on the front & my car now stops like the average car ..I can feel the rear grand Am brakes come in just behind the front and my pedal has more movement before the brakes start grabbing,but the pedal is firmer.. ..when doing the Grand Am upgrade on the front you should install top quality pads on the rear to help restore balance , this is the principle I used with the low quality pad on the rear Grand Am,worked out great for me.(for once!)
[This message has been edited by uhlanstan (edited 01-03-2011).]
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06:21 PM
Blacktree Member
Posts: 20770 From: Central Florida Registered: Dec 2001
On my car, the Grand Am front brake upgrade added about 8 lb per wheel, according to my bathroom scale. You can blame that on the cast iron calipers, and double-walled rotors.
I've also been looking for some lighter calipers to replace the Grand Am ones. I got a pair of the Camaro / S10 front calipers (which are typically used with the 11" brake rotors), but haven't had a chance to mock up some adapter plates for them. They are noticeably lighter than the Grand Am calipers, though.
Maybe you could try adapting '88 Fiero calipers to fit the front?
I had read in another thread that Held (HT) whatever it is now? is working on a package to install '88 brakes onto 84-87's. Anyone know if this is true? Or what about the ssbc calipers some people have used with Lebaron rotors?
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08:12 PM
ace5514 Member
Posts: 692 From: west long branch, nj, usa Registered: Nov 2008
love tat pic above with blue caliper! that is what i was looking to do also. 88 calipers with lebaron rotors on 87 gt. perfect! i may try to make it this spring if someone doesn't make it for easonable money first.
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09:37 PM
Jan 4th, 2011
82-T/A [At Work] Member
Posts: 25005 From: Florida USA Registered: Aug 2002
I had read in another thread that Held (HT) whatever it is now? is working on a package to install '88 brakes onto 84-87's. Anyone know if this is true? Or what about the ssbc calipers some people have used with Lebaron rotors?
I have an 85GT with an 88 rear cradle. This made it a bit more difficult to find a decent brake upgrade.
My solution was to use 12" vette rotors and 88 fiero calipers all around. It works well but will not fit under stock wheels.
The problem comes in the design of the 84-87 knuckles. Without enlarging the rotors there is a major clearance issue with 88 brake calipers on the ealier cars. Going with a 12" or larger rotor gives the room needed. Even 12" is tight and, for me, required a minor amount of grinding on the knuckle for caliper clearance. Stock 88 rotors absolutely will not work. Unless they have found a way to move the calipers to another side of the rotor. From what I've seen stock 88 rotors and calipers will not work on 84-87 without significant modification to the suspension also.
FYI. My scale said I added 3.5lbs per wheel with my brake upgrade. The 12" rotors were heavier but the 88 calipers were lighter (1/2 alluminum). I'm suprised the Grand Am set is so heavy.
[This message has been edited by Fieroseverywhere (edited 01-04-2011).]
Fieroseverywhere, Do you have a cad drawing of the brackets needed to mount 12" vette rotors/'88 calipers on a 84-87 car?
Unfortunately, no. Also with my 88 cradle I only have those brackets on the front. The rear ones for an 84-87 would be very different then the front. I did take measurments at one point. If you want I can send them to you. In the mean time here is a pic to get an idea of what they look like... From the top. From the bottom.
[This message has been edited by Fieroseverywhere (edited 01-12-2011).]
as to the balance - I have the Grand Am up front, and stock rears - and the front braking is way to much. and, it is NOT due to my rears being old/out of shape. I am in the process of putting on the Cadillac Seville brakes on the rear to make for a better balance. By the math per the cyl bores - it should be back to near stock for balance. Just waiting for decent weather outside to make it happen. got the Seville calipers from the you-pull-it, and got rebuild & hardware kits for them. sanded them smooth & painted them. the brackets weere made by DPwood (I think? ArnsGT knows more).
Yes the brackets are made by DPWood and designed by Arns85GT
The Grand Am only on the front is just not satisfactory. The piston is bigger and the balance is thrown off. Also, it requires more pedal.
The Seville piston is just a hair smaller than the Grand Am in diameter, but seems to have about the same volume. The balance is darn near perfect.
I also recommend the S10 booster conversion as a matter of course. It makes such a huge difference regardless of which way you go. And btw, Rodney's adjustable banjo is a pretty good idea too.
Unfortunately, no. Also with my 88 cradle I only have those brackets on the front. The rear ones for an 84-87 would be very different then the front. I did take measurments at one point. If you want I can send them to you.
I also have an 88 cradle in the rear of my 86. What I have gathered is that a 12" vette rotors and 88 calipers will be just as light as any other brake upgrade and would be very low cost. I wouldn't Mind any measurements you have. Also I wouldn't mind getting measurements for the 12" vette rotors, to see if I can find some 2-peice willwoods.
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06:21 PM
Fieroseverywhere Member
Posts: 4242 From: Gresham, Oregon USA Registered: Mar 2006
I also have an 88 cradle in the rear of my 86. What I have gathered is that a 12" vette rotors and 88 calipers will be just as light as any other brake upgrade and would be very low cost. I wouldn't Mind any measurements you have. Also I wouldn't mind getting measurements for the 12" vette rotors, to see if I can find some 2-peice willwoods.
For the adapter brackets... Plates are .5"x2.5"x4"
Tubes are .83" long with .75"OD and .5" ID. The bolt holes caliper side are tapped, other side are drilled straight through. Don't forget to clearance for the caliper piston. As for placement of the tubes I suggest measuring those out (actually I suggest measuring everything yourself). Mine were not made correctly and I recently had to fix them. I did not take new measurments afterwards. I also had to clearance a very smal amount from the knuckle so the calipers would slide correctly. Sure beats the alternative though. Before the fix the pads rode off the edge of the rotor.
For the rotors just look for 94 vette front rotors. Willwood has lots in that diameter (12.01" OD x .80" thick). However they do not offer a 5x100 bolt pattern that I've ever seen. Maybe as a custom order but nothing off the shelf.
[This message has been edited by Fieroseverywhere (edited 01-12-2011).]
The measurements I really need are the rotor hat heights for the front and rear vette rotors. They are different, I just don't know by how much. With that I can figure out which rotors hats I would need. Wilwood makes off the shelf rotors for the rear of the vette only.
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10:10 PM
Jan 13th, 2011
Fieroseverywhere Member
Posts: 4242 From: Gresham, Oregon USA Registered: Mar 2006
The measurements I really need are the rotor hat heights for the front and rear vette rotors. They are different, I just don't know by how much. With that I can figure out which rotors hats I would need. Wilwood makes off the shelf rotors for the rear of the vette only.
According to the measurments put out by concentric...
Outer dia: 12.01" Height: 2.19" Nom Thick: .79" Min Thick: .72" Hub Reg: 2.78" Bolt Size: .51" Bolt Circle: 5 x 4.75" Weight: 14lbs
The rears have a height of 1.97" as a comparison. Hope this helps.
[This message has been edited by Fieroseverywhere (edited 01-13-2011).]
I did a similar solution to fieroseverywhere, but found that with that caliper placement, it would interfere with the shock when turning to complete lock. I did have some brackets designed and built to rotate the caliper up, offering a stronger mount, and clearance for the shock.
Using 88 corvette rotors front and rear, the Fiero now stops like never before. Since the calipers are fiero calipers, the proportioning is correct, and no hydraulic changes are needed.
I have images that I would post, but the image poster is not so friendly for me. PM me and I'll gladly share more details.
