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Post by Larry Madsen on Jun 30, 2020 18:38:27 GMT -5
![]() I might have mentioned previously (either here or the old place) I was changing out the rear gears on the Camaro. Years ago we put in some 3.08:1 gears because we were doing a lot of highway driving to out of town car shows. Now it's my daily driver and about all I do is drive to and from work on Flamingo Road, about 6 miles each way stop light to stop light. Those 3.08:1 gears are drivable, but take offs from a stop could be easier and the RPM at city street speeds are sitting in a bad place in 4th gear and also a bad place in 3rd gear. Drivable, but not pleasant. I purchased a set of 3.55:1 gears and a Yukon posi unit to go along with it. I virtually never let anyone else work on this car, but this gear swap is a bit out of my comfort zone so I took the car to my regular shop. They got the job done though it took them two tries. They tried to give the car back to me with a loud growl coming from the differential ... Took me about half a block to get to 45MPH, hear the problem and turn around. They had the clearances too tight and had to re-shim the assembly to loosen it up a bit. The noise is now gone. I get home and discover I have no E-brake. Upon inspection I discover the passenger side piston had been backed all the way into the brake caliper and never adjusted back to proper position. PITA having to correct this, but not terribly difficult. Then I have the brakes locking up on me while driving, seemingly a bit intermittent. I automatically assume it's the E-brake still having a problem and acting up. After some trouble shooting I discover it's all four wheels locking up ... I pull the vacuum off the power booster and drive the car to see what happens. Problem found, it's the power booster causing the problem. With no vacuum to the booster the brakes don't lock up. I start looking for the correct power booster. Not a straight forward search since this entire brake system is an upgrade to the car. The rear calipers are 79 Cadillac. The front calipers are about 72 Monte Carlo and memory was telling me the booster and master cylinder were 78 Corvette. I finally get it sorted out and know which booster to purchase. I go to work on Sunday and get to thinking, my approach and theme with this car is to make it as simple as possible. Very spartan mechanically. I had already eliminated the power steering, the windshield washer, the air conditioner, etc. It occurs to me that I don't need the power booster at all. I had put this kit on the car back when we had four wheel manual drum brakes all around. The four wheel power disc brakes were an enormous upgrade. However, even four wheel manual disc brakes are a huge upgrade from those original drums. Queenie once drove this car a bit and a lot of the fancy stuff was for her, now days I am the only driver of the Camaro. Manual disc will be just fine with me and it gets me to a simpler even more spartan place with the car. One less thing to worry about going bad or breaking ... again. Ordered a new master cylinder with a smaller bore And I should be good to go. Elimination of this big boy will make changing spark plugs at the rear here a lot easier too.   DSC_2207 by Larry Madsen, on Flickr |
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Post by De ville on Jun 30, 2020 23:31:17 GMT -5
In a perfect world you'd have a full size vehicle lift, and I bet you would have tackled the rear end head on. One can dream! Cool just having a hot rod to work on though!
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Post by Lefty Rev on Jul 1, 2020 11:55:27 GMT -5
Larry,
I'm marveling at all the mechanical information that must be archived in your brain! A true database of automotive history and engineering!
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Post by Ragtop on Jul 1, 2020 17:19:35 GMT -5
Keep posting this stuff about that cool old car. It's interesting!
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Post by budg on Jul 1, 2020 17:38:10 GMT -5
I’ve always wondered about the 4 disc manual brake idea. I have front disc on my 72 Olds. I have factory power steering and am going to replace the gear box with a tighter ratio. It takes a looong time to turn from one side to the next.
I hear ya on not wanting others to touch the car. I’ve done well so far and even redid my rear seat and door panels. They came out ok.
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Post by Larry Madsen on Jul 1, 2020 19:17:21 GMT -5
Thanks for the interest guys.
I'll report back on the results when I'm done with the swap.
I'm sure it will be fine with me.
The caliper mishap was purely the mechanic when he put the rear axle back together.
The booster pretty much had to be coincidence.
I' going to a 1" bore on the master cylinder and if I want more pressure I can drop to a 15/16" or 7/8" bore to get more psi going out the lines.
My understanding of brakes it that the drums are very very efficient, so mch so that you have to run severe pressure reduction (like 250psi) on them or they are prone to lock up. In the end that huge pressure reduction for safety reasons makes them pretty ineffective out on the road. Sounds crazy.
Disc on the other hand will take 3000psi and don't care one bit. Really pretty hard to lock them up. And they cool very quickly.
Less efficient method is better in practice.
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Post by rangercaster on Jul 1, 2020 19:59:57 GMT -5
My neighbor in the 60s ... had a sister in law who would let him....
Borrow her car ... a 67 era Z28 Camaro ... the one that hauled serious ass ...like when you do 60 in first gear ... a race car ... and he was a professional ...
I'm ten years old and he invites me to go for a ride ... so we proceed to drive past cops who don't care ...at well over 100 mph ...
The cops knew the car ...
They also knew they would never catch the car ...
I am still alive ...
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Post by jhawkr on Jul 1, 2020 20:34:44 GMT -5
Drum brakes are self-energizing in that as the shoes are brought into contact with the rotating drum they sort of wedge into the drum effectively multiplying the contact force and increasing brake power. Maybe poorly explained but I haven’t touched a drum brake in many years.
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Post by Larry Madsen on Jul 1, 2020 20:40:51 GMT -5
Drum brakes are self-energizing in that as the shoes are brought into contact with the rotating drum they sort of wedge into the drum effectively multiplying the contact force and increasing brake power. Actually pretty well explained. That self energizing characteristic is why they have to be careful on the PSI going to the brake cylinder, as I understand it. |
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Post by rangercaster on Jul 1, 2020 22:43:18 GMT -5
Drum brakes dont really stop your car ... disc brakes might ...
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Post by Larry Madsen on Jul 6, 2020 14:40:52 GMT -5
Well, when I ordered the new master cylinder I somehow missed the part of the discussion about ... "the order won't ship for two to three weeks". While pushing the brakes through a dead power booster is not exactly desirable, I guess I'll be doing it for a while longer. I do have a new fuel pick-up and sending unit to install. If you need me I'll be out in the garage siphoning a few gallons of fuel from the tank so I can drop it to the floor. If I come back in spitting on the desk, you'll know why. |
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Post by Larry Madsen on Jul 7, 2020 18:18:11 GMT -5
The project is completed.  In the process I cleaned up the tank, not that it's really visible, but it was pretty dirty and some paint drips and overspray from painting the car. It's stainless steel, so some work with paint stripper, lacquer thinner, steel wool and some rags it's nice and shiny clean. I purchased some new tank straps to hold the tank up. The old ones were really showing their age. I had bought a new pigtail for the sender when I rewired the rear of the car, so I finally got that installed. I must confess though ... the new sender has a rather large float such that when I installed the sender/pick-up tube/float into the SMALL hole in the top of the tank they pretty much don't fit. They have to all go through the hole at the same time. My first try I forced things a bit too much and put a nice ding in the float. I can't tell if the float is hollow or solid. If it's hollow that ding could allow fuel into the float and put me right back where I was before I started this project.  Fingers crossed on the float being solid and the ding won't matter.  Anyway, the car runs again, so I can go to work tomorrow. |
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Post by fkaJimmySee on Jul 8, 2020 6:06:48 GMT -5
Hi Larry -- hope you two are doing well in these virus-laden times. I can buy into all the work except removing the a/c from the car. Maybe because it's only a short drive for you to work, but it gets mighty h-o-t out there this time of year!
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