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Topic Review (Newest First)
02-28-2019 08:44 AM
mainstreetprod
Quote:
Originally Posted by Bob37pont View Post
My braking issue started with the booster that was on the car went bad. It was reputed to be from the same '74 donoor that the front clip came from. There is only one booster offered for '75-78 MII, and it didn't match up with what I had.

I went with an after market 7" dual diaphragm booster, dual MC with proportioning valve combo (brand new) I got from a friend. After mounting and making adjustments to get a straight push from the pedal to the booster, I had better brakes, but they still seemed a bit weak. That's when I went for the 11's. Better, but still not quite right!

Finally figured out the proportioning valve was for 4 wheel discs instead of disc front/drum rear. Changed that out and now have proper braking.

Might possibly been OK with the original 9" discs, but like cubic inches, you can't go wrong with more brake power!
Do you recognize this booster? I think it's working but not that well. Also, I could well have the same proportioning valve issue, will need to check mine and see what I have.
02-28-2019 06:28 AM
Bob37pont My braking issue started with the booster that was on the car went bad. It was reputed to be from the same '74 donoor that the front clip came from. There is only one booster offered for '75-78 MII, and it didn't match up with what I had.

I went with an after market 7" dual diaphragm booster, dual MC with proportioning valve combo (brand new) I got from a friend. After mounting and making adjustments to get a straight push from the pedal to the booster, I had better brakes, but they still seemed a bit weak. That's when I went for the 11's. Better, but still not quite right!

Finally figured out the proportioning valve was for 4 wheel discs instead of disc front/drum rear. Changed that out and now have proper braking.

Might possibly been OK with the original 9" discs, but like cubic inches, you can't go wrong with more brake power!
02-27-2019 07:53 PM
mainstreetprod
Quote:
Originally Posted by Bob37pont View Post
On my Pontiac the front track width was about 3 narrower than the Camaro rear track (some of that was the tires, 235 vs 215), and I had plenty of clearance inside the fenders for the wider front track. Mine had GM pattern 9" rotors when I got it, didn't have any worries about spacers/adapters.
Bob, I have a question for you or anyone else familiar with stock 9" brakes on large street rods (say 3500 lbs plus). I would expect lackluster performance since they were designed for a Pinto, but mine seem worse than that- stepping on them is very similar to a mechanical brake system, not remotely capable of a panic stop, "stomp and pray" . The only car I've owned with brakes this bad was a 1919 Chevy. I'm wondering if something else is wrong with mine. I have jacked up the wheels and confirmed they all are working. Also confirmed that my brake booster is operational.

As far as the track goes, checked today and found the rotors have 1" wheel adapters and front track is narrower than back, so any widening of the track by a new disc system, won't be an issue.
02-25-2019 06:12 AM
Bob37pont On my Pontiac the front track width was about 3 narrower than the Camaro rear track (some of that was the tires, 235 vs 215), and I had plenty of clearance inside the fenders for the wider front track. Mine had GM pattern 9" rotors when I got it, didn't have any worries about spacers/adapters.
02-23-2019 03:41 PM
Hotrod46 You might even be narrower when you lose the adapters. Should be close. If you are narrower, a thin spacer will get you back to where you are now.

Be sure to check bolt pattern on your current wheels before deciding a brake kit.
02-23-2019 01:01 PM
mainstreetprod
Quote:
Originally Posted by Hotrod46 View Post
Keep in mind that any kit that uses Granada rotors will widen the track about 1" (1/2" per side). The Camaro rotors may do the same, but I have never used them.

There are some kits that use custom hubs and separate rotors that don't change the track as much. I have a Baer kit on my current project that only adds 1/4" to each side.

Check tire clearance to the fenders well to make sure you don't run into trouble.
Only had my car a couple of weeks and haven't had the wheels (5 lug 17" mags) off yet, but I assume if the 9" brakes are not aftermarket that I have wheel adapters to go from 4 to 5 lug, which should make the track similar to Granada rotors. Correct?
02-23-2019 12:51 PM
mainstreetprod
Quote:
Originally Posted by Hotrod46 View Post
Keep in mind that any kit that uses Granada rotors will widen the track about 1" (1/2" per side). The Camaro rotors may do the same, but I have never used them.

There are some kits that use custom hubs and separate rotors that don't change the track as much. I have a Baer kit on my current project that only adds 1/4" to each side.

Check tire clearance to the fenders well to make sure you don't run into trouble.
Only had my car a couple of weeks and haven't had the wheels (5 lug 17" mags) off yet, but I assume if the 9" brakes are not aftermarket that I have wheel adapters to go from 4 to 5 lug, which should make the track similar to Granada rotors. Correct?
02-23-2019 11:45 AM
Hotrod46 Keep in mind that any kit that uses Granada rotors will widen the track about 1" (1/2" per side). The Camaro rotors may do the same, but I have never used them.

There are some kits that use custom hubs and separate rotors that don't change the track as much. I have a Baer kit on my current project that only adds 1/4" to each side.

Check tire clearance to the fenders well to make sure you don't run into trouble.
02-23-2019 09:18 AM
mainstreetprod
Quote:
Originally Posted by Bob37pont View Post
This is the brake kit I used, it's a true bolt on. Only install tip is to sand the paint some from the outside of the replacement oil seals so they install easier and don't distort, read the reviews on the website. They also offer the kit with a Ford bolt pattern.
https://www.speedwaymotors.com/Musta...M-BP,2007.html
Thanks for posting that, without a recommendation from someone buying a kit is just a shot in the dark. Price is great too!
02-23-2019 05:46 AM
Bob37pont
Quote:
Originally Posted by mainstreetprod View Post
As it turned out, my problem with the ride was mainly flat spots on the tires from 15 years storage. After driving a mile or so and getting used to the fact that it doesn't ride like a stock '48 Lincoln (a mobile sofa), I'm OK with the ride. And the ride height is perfect. So I guess what I have to decide is whether the suspension has adequate travel, and I'd say it's an inch or two short of that. And if I change the springs, I might as well soften the ride a notch or two. The trick is figuring out what spring to buy- I don't want to do three trial and error tear down and rebuilds of the suspension. While I'm at it I'll replace the pathetic 9" brakes with 11".
This is the brake kit I used, it's a true bolt on. Only install tip is to sand the paint some from the outside of the replacement oil seals so they install easier and don't distort, read the reviews on the website. They also offer the kit with a Ford bolt pattern.
https://www.speedwaymotors.com/Musta...M-BP,2007.html
02-22-2019 03:47 PM
mainstreetprod
Quote:
Originally Posted by johnsongrass1 View Post
So now you have to decide what your want. A softer or stiffer ride? The same ride quality but not bottoming out?
If it's just ride height and you're okay with the quality then you need 3-4inch longer spring in the same rate so the adjuster nut can have more upward travel to set the ride height where you want it.

As it turned out, my problem with the ride was mainly flat spots on the tires from 15 years storage. After driving a mile or so and getting used to the fact that it doesn't ride like a stock '48 Lincoln (a mobile sofa), I'm OK with the ride. And the ride height is perfect. So I guess what I have to decide is whether the suspension has adequate travel, and I'd say it's an inch or two short of that. And if I change the springs, I might as well soften the ride a notch or two. The trick is figuring out what spring to buy- I don't want to do three trial and error tear down and rebuilds of the suspension. While I'm at it I'll replace the pathetic 9" brakes with 11".
02-22-2019 03:03 PM
johnsongrass1
Quote:
Originally Posted by mainstreetprod View Post
So adjusting the nut downward will lower the height? I assumed the reason they were adjusted so far upward was to get the car down on the ground. Also, it seems to me like the spring characteristics will change as the nut is adjusted down - coils will open up, suspension will have a lot more travel, and ride should improve. A compressed spring with little travel should have a rougher ride.
It doesn't work like that exactly.
Coil spring rate is dependent on three things. The wire diameter, the width of the spring and the number of coils.
On coil overs, you aren't changing any of the above unless you run the adjuster up to the point some coils are touching. That reduces the number of active coils and makes the spring stiffer but your lose the travel to soften the ride. Assuming they are not touching, or coil bound as we call it, all your doing is adjusting the relative position of the spring to the frame of the car. Basically adjusting the ride height and that's it.
If the car weighs 4000lbs, the front weighs 2000lbs and each corner weighs 500lbs, than 250lb spring would compress 2". Moving the nut up or down doesn't change the amount of weight the spring has too hold up. In this case it's 500lbs.
A longer 250lb spring lowers the nut but still compresses 2". A short 250lbs spring raises the nut but still compresses 2".
The idea is too find the weight the spring has to hold up, selecting a rate that holds up the car and is still long enough to put the adjuster nut somewhere in the range of it's adjustable range.
In your case, the spring is too short if you want to keep the ride how it is(coil binding), it's too soft and too short if you want a stiffer ride( coil binding and won't hold up the car).
So now you have to decide what your want. A softer or stiffer ride? The same ride quality but not bottoming out?
If it's just ride height and you're okay with the quality then you need 3-4inch longer spring in the same rate so the adjuster nut can have more upward travel to set the ride height where you want it.
02-22-2019 11:21 AM
'48 Austin Adjusting the nut downward will lower the ride height. It will not change ride characteristics. If you don't believe us, try it and you'll learn for yourself. A number of people posted "you need a stiffer spring, higher load rating, or a higher spring rate". They all mean the same thing. You have too much weight up front for the springs you have. CHANGE THE SPRINGS.
02-22-2019 08:06 AM
mainstreetprod
Quote:
Originally Posted by ericnova72 View Post
With the adjusting nut on the bottom, all that will do is lower the ride height....it won't change ride stiffness at all. To change ride quality, you've got to change the spring rate.
So adjusting the nut downward will lower the height? I assumed the reason they were adjusted so far upward was to get the car down on the ground. Also, it seems to me like the spring characteristics will change as the nut is adjusted down - coils will open up, suspension will have a lot more travel, and ride should improve. A compressed spring with little travel should have a rougher ride.
02-21-2019 11:15 PM
ericnova72
Quote:
Originally Posted by mainstreetprod View Post
So can someone tell me what would happen if I simply adjusted the coil over adjustment nuts downward, say an inch? Obviously suspension travel increases, but what happens to ride height and lower control arm position? Right now the bottom of the stock arms are exactly parallel with the pavement.
With the adjusting nut on the bottom, all that will do is lower the ride height....it won't change ride stiffness at all. To change ride quality, you've got to change the spring rate.
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