American Muscle Cars Australia
Tech Talk & Articles => GM Cars => Topic started by: 1977 Transam on March 03, 2015, 11:05:31 AM
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Hi everyone.
Hoping someone knows where I can get a disc brake conversion kit for a 1977 Transam thanks.
I tried sizing up a Baer Brake kit with 12 inch disc and 4 piston setup but it won't fit the snowflake 15 inch rims.
Any help would be appreciated.
I don't want to change to a low profile rim though to upgrade the brakes.
Need a handbrake allocation in it as well though.
Thanks.
Tommy
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Try this company...www.p-s-t.com (http://www.p-s-t.com). On the home page up the top corner type in this part number: DBKRAFXRD07.
Looks pretty comprehensive.
Good luck.
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Thanks Chris. I'll have a chat to them and see if they will work with the original rims.
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Have you considered using bigger drums on the rear instead of a disc conversion?
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I haven't thanks. What would be the benefits over disc please?
Any idea what type I could use to fit into the 15 inch rims?
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Larger braking surface which will give you firmer pedal feel and longer life. I am sure the biggest option drum brakes will still fit inside 15" wheels but bonnevista would know better.
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One of our forum members, LeighP went this route with his '71 Firebird. As far as I'm aware, he was very happy with it. I think it's bought as a kit and basically uses rear brakes from a full size car. Another advantage of staying with the drum rear would be having no dramas with your parking brake.
Sent Leigh a message, I'm sure he'll get back to you.
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Yeah, I used a Master Power Brakes kit that fits new B body Police(HD) finned drums onto the back of my 71.
Simple bolt on mod that leaves you with working Park brake and will fit 15" wheels.
The drums come as a unit with backing plates and brakes etc.....everything brand new. Classic Industries is a reseller of these and I scored a good deal when Classic's were having a sale.
(http://i104.photobucket.com/albums/m195/TA76400/71%20Firebird/PA230023.jpg) (http://s104.photobucket.com/user/TA76400/media/71%20Firebird/PA230023.jpg.html)
This shows 15" Rally wheels.....they clear.
(http://i104.photobucket.com/albums/m195/TA76400/71%20Firebird/PA230025.jpg) (http://s104.photobucket.com/user/TA76400/media/71%20Firebird/PA230025.jpg.html)
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I went with Chevy C10 drums on the back of the Chevelle. I found the bigger drums work really well & the park brake holds good.
Fits inside a standard 15" wheel. I think the drums are 11" Looks pretty similar to what Leigh has in the pics.
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Thanks for the info on the drum brakes guys.
Leigh were yours 11 inch drums as well please?
I was looking at these yesterday from Willwood. Waiting to hear back from them about whether they would fit in my rims.
http://www.wilwood.com/BrakeKits/BrakeKitsProdRear.aspx?itemno=140-11397-DR (http://www.wilwood.com/BrakeKits/BrakeKitsProdRear.aspx?itemno=140-11397-DR)
Curious about drums now. Would they have the same stopping power as the Willwoods?
I'm assuming that the discs would be lighter and stay a lot cooler during operation.
Still learning about the differences though.
Tommy
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Forgot to ask, "What size drums would be on mine at the moment"?
Not sure if anyone knows.
Thanks.
Tommy
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Found this article comparing drum vs disc brakes which I found interesting.
http://www.edmunds.com/car-technology/brakes-drum-vs-disc.html (http://www.edmunds.com/car-technology/brakes-drum-vs-disc.html)
Tommy
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Forgot to ask, "What size drums would be on mine at the moment"?
Not sure if anyone knows.
Thanks.
Tommy
I think they're 9 inch from memory.
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Yep, B body drums are 11" vs the stock 9" diameter.
Most of the braking on a 2nd gen is accomplished by the discs on the front. The large drums are effective and unless you're using them for track work, I can't see heat build up being an issue.
Whatever you do, be prepared for the possibility of needing an adjustable bias valve.
Be sure to double check the seated depth of the booster's operating rod vs the piston in your mastercylinder.....problems with this surfaced on my car and others when combining repro mastercylinders and repro boosters.
You won't need to change the factory booster/master combo if you're only switching to 11" drums. You will need to replace the mastercylinder if you're switching to disc/disc, and in some situations, you may need to change the booster as well (factory disc/disc WS6 booster isn't the same as the earlier disc/drum booster from memory).
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And in my series of car (maybe others), full size station wagons had 12 inch drums on the rear.
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12" drums!!.....holy crap.....no wonder you call your car a barge.... :bats:
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Also, (and I'm dredging the depths of my memory here) the midsize Oldsmobile (Cutlass/F85) used a wider drum on the rear of their station wagon. They still used a 9 inch drum, but it was the drum they used to use on the front with a wider shoe. The backing plate was the weird part, as it had a funny offset to accommodate the wide shoe.
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Hi guys.
I was asked a question today from a parts supplier in the states.
He wants to know what the axle flange offset measurement would be on my Transam.
Would anyone know what it is please or where I can find this answer.
Mister google hasn't offered me an answer as yet.
Thanks.
Tommy
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Nothing here to measure, so I can't help.....but thats an odd question to ask. There are only two different 2nd gen 10 Bolt axles.....Drum brake, and Disc brake. The axle register (the raised seat for the drum centre) is a little bigger (wider) I seem to recall on the disc brake axle.
That could be what he's asking?
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I know Leigh. It's very odd.
I've been searching everywhere for the answer. Two suppliers gave me the option of 2.75" or 2.81".
I found this on the net...........
http://www.crankshaftcoalition.com/wiki/images/thumb/a/a7/Rear_end_axle_flange_id.jpg/800px-Rear_end_axle_flange_id.jpg (http://www.crankshaftcoalition.com/wiki/images/thumb/a/a7/Rear_end_axle_flange_id.jpg/800px-Rear_end_axle_flange_id.jpg)
No info on the offset though.
Didn't think upgrading brakes would be so difficult.
One thing is for sure, companies sell their brake upgrade kits noting it's for a specific model, but when you want to buy it they ask you to double check the measurements.
Why promote a part for a vehicle if they don't know if it's going to fit. And to top it off they know nothing about the vehicle they are selling parts for.
You would think they have a listing of the offsets if they are going to ask the question.
The first company that can confidently provide me with info on a brake upgrade install on my car will get the sale.
I'm fed up with it now.
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Have you tried dave at ponti world
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Yeah had a look a couple of months ago but am after a performance braking package with drilled and slotted disc's and 4 pistons.
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I know Leigh. It's very odd.
I've been searching everywhere for the answer. Two suppliers gave me the option of 2.75" or 2.81".
I found this on the net...........
http://www.crankshaftcoalition.com/wiki/images/thumb/a/a7/Rear_end_axle_flange_id.jpg/800px-Rear_end_axle_flange_id.jpg (http://www.crankshaftcoalition.com/wiki/images/thumb/a/a7/Rear_end_axle_flange_id.jpg/800px-Rear_end_axle_flange_id.jpg)
No info on the offset though.
Didn't think upgrading brakes would be so difficult.
One thing is for sure, companies sell their brake upgrade kits noting it's for a specific model, but when you want to buy it they ask you to double check the measurements.
Why promote a part for a vehicle if they don't know if it's going to fit. And to top it off they know nothing about the vehicle they are selling parts for.
You would think they have a listing of the offsets if they are going to ask the question.
The first company that can confidently provide me with info on a brake upgrade install on my car will get the sale.
I'm fed up with it now.
Rebuild your drums using quality parts, they'll work fine.
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I will buy shoes and cylinders for the original drum setup and see how we go.
Do you think after 38 years the internal components like the springs will need replacing?
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I've put 212,000 miles on my barge in the last 13 years. The only thing I've replaced are the self adjusters and (of course) a few sets of brake shoes and they work well. Having said that, all the stuff is available to rebuild them 'like new', so it wouldn't hurt.
I'm only speaking from my experience, but I think the biggest problem drum brakes have in our sort of car is lack of use. There's a lot of moving parts in drum brakes and they need to be moved regularly.
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I may as well spend the little extra and make it like new.
You certainly put a lot of mileage on your ride.
I need to get out and about a bit more.
After it gets the paint job refreshed in April I'll be happier to show it off.
Bit embarrassed with the way the paint has bubbled on her.
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I've had other american cars that I've put more mileage on in less time. When all these cars were new, they were built for use (and used as) as daily transport.
As far as being embarrassed about the paint showing it's age, don't worry about it. What others think about your car isn't important, as long as you like it. The paint is lifting off my car in plenty of places, but that's just what happens as they get older. Far more important for me is that I can jump in that car and drive it to Adelaide and back with confidence that it will perform flawlessly.
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The Transam starts first time every time which is a bonus.
Guess I just need to look at the bright side. Glass half full eh. :)
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The Transam starts first time every time which is a bonus.
Guess I just need to look at the bright side. Glass half full eh. :)
Exactly. You own a '77 Trans Am. How many other people do you know have one?
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Not many. As long as I have money in the bank account I will keep it.
Puts a smile on so many people's faces which is what makes it worthwhile for me.
Probably the same reason why everyone in the club has one.
And I'll never get sick of that v8 sound.........