PY Online Forums - Bringing the Pontiac Hobby Together

PY Online Forums - Bringing the Pontiac Hobby Together (https://forums.maxperformanceinc.com/forums/index.php)
-   Pontiac - Street (https://forums.maxperformanceinc.com/forums/forumdisplay.php?f=418)
-   -   73-77 A body disc brakes on a 65 Tempest (https://forums.maxperformanceinc.com/forums/showthread.php?t=869536)

importsmasher 10-01-2023 01:45 PM

73-77 A body disc brakes on a 65 Tempest
 
I am supposed to pick up a 75 LeMans parts car this week. I'm wondering if the front disc brake setup would work on my son's 65 Tempest. Many years ago in high school, we tried to put a similar setup on my brother's 69 Judge, but as I recall the lower ball joint didn't fit (but memory is vague).

Can anyone tell me if there's a way to make it work? And will it clear 14 inch wheels?

Thanks,
Importsmasher

i82much 10-01-2023 02:19 PM

i have 72 chevelle disc on the front of my 65 with 14 inch wheels. if memory serves, the spindle was different? and i think there may only be some 14" wheels that fit disc.

geeteeohguy 10-01-2023 03:34 PM

'69-'72 disc brake A body spindles and brakes will bolt right on, and work perfectly. They will not change the front end geometry. '75 and up won't work. Neither will the F body spindles.

importsmasher 10-01-2023 03:58 PM

Quote:

Originally Posted by geeteeohguy (Post 6458130)
'69-'72 disc brake A body spindles and brakes will bolt right on, and work perfectly. They will not change the front end geometry. '75 and up won't work. Neither will the F body spindles.

I knew the 69-72 will bolt on. I was hoping there was a way to adapt the 73-up brakes. Oh well, it was worth a shot....

As for the F body, I've read somewhere you can use them on 64-72 A bodies if you used a different upper control arm. No idea if that's actually true. My brother was going to try that route with his 68 Skylark, but ended up not doing it.

Thanks,
Importsmasher

Scarebird 10-01-2023 04:26 PM

It is, but more problems than it is worth.

importsmasher 10-01-2023 06:41 PM

Thanks all, that answers my question. My son will just have to find his own disc brakes lol.

Importsmasher

jerry455 10-01-2023 06:56 PM

I installed the 11" drum brake set up from a 1977 Pontiac Lemans onto my 1976 Firebird. It originally had 9.5" drums on the Firebird. I put a B body spindle with the 1LE rotors on the front of the Firebird also.

Schurkey 10-09-2023 03:49 PM

The '75 disc brakes will fit just fine once you get lower ball joints installed, and outer tie rod ends to suit the knuckle tapers. That is the basis of the old "Tall Spindle" H-O Racing Specialties disc conversion. I've done two vehicles with those parts. First one, I bought the H-O kit. Second one, I took the brand-new '75 ball joints to the machine shop, had them carve the diameter a little smaller. Measure the old ball joint press-fit diameter, make the later ball joints the same diameter. Then get newer tie rod ends of the right thread diameter and thread pitch, so that both the ball joint stud taper, and the tie rod end stud taper matches the knuckle.

Supposedly, bump steer is not optimum. I've never noticed.

Overall, it works great. Better geometry for handling, better geometry for getting the knuckle installed--don't have to fight the spring as much.

You'll want new control arm bushings, but that's pretty-much a given on these cars.

Scarebird 10-09-2023 06:10 PM

This was a meh solution 20 years ago and a poor one now. You will lose a lot of steering radius and bump steer is bad.

Don't do it.

Schurkey 10-09-2023 08:25 PM

It beats the OEM drum brakes. It costs almost nothing if you consider the original tie rod ends and lower ball joints may be wiped-out and need replacement anyway, as those (and a bunch of alignment shims, and perhaps longer control-arm cross-shaft bolts holding it to the frame) are the only "mandatory" parts aside from the steering knuckles, rotors 'n' bearings, calipers 'n' pads, combination valve, and brake hoses, which MIGHT all be usable from the donor vehicle. I used all of that from the '75 Nova donor vehicle--including the booster and master cylinder--for my first A-body. All the normal "wear" parts were in great condition. The second one got new pads, new brake hoses, rebuilt booster 'n' master; and the rotors cut.

It's a functional, work-able, easy and inexpensive disc brake upgrade. Yes, it's not an optimum solution. It is COMPLETEY possible to spend five or ten times as much money, and get bigger, better brakes along with better geometry for the suspension.

Scarebird 10-09-2023 08:43 PM

I disagree.

We sold 80 or so of those HO-style spindle sets 20 years ago, machined them to fit the stock tie rods and ball joints. I had 2 vehicles with them personally.

In the interim, the cost of disc conversions has halved - Summit has the basic OEM style wheel kits under $600 to your doorstep. The OEM style is superior, especially if you use a tall lower ball joint to correct the bump issue.


CROCIE JR 10-09-2023 11:16 PM

There is bumpsteer with the F body spindle conversion H-O Racing pioneered. It is still a great way to raise the front roll center cheaply. Not to mention the camber gain when the ride height is corrected (lowered). Not many people have measured the bump steer at ride height. When you did, what was your findings at +/- 3" from ride height and how did it affect your lap times, slalom speeds or tire wear? Is there bump steer yes, does it make you slow at the track where these things can be quantified, no. Only you make you slow. Keep in mind in 92' these H-O cars would outhandle Modern performance cars of the time, including a ZR1, as proven in Car Craft magazine. Modern rubber has made this conversion even more effective. Before anyone discredits the conversion, ask yourself if you think you can find the limits of your car with a properly set up suspension and "Knuckle Sandwich" conversion and I will show you a better driver than me and most. It works. Its still cheap. And works better than you can drive.

CROCIE JR 10-09-2023 11:22 PM

Scarebird. Usually folks were putting in a higher effort steering box and we would just increase the internal stops of the new or reman box. So fixed your problem there. Our custom box guy would charge nothing for this service. Today you can request it.

hgerhardt 10-10-2023 10:22 AM

I came in 2nd in the '91 Car Craft Real Street Eliminator in my '66 GTO. My car had the H-O tall spindle kit (the "Knuckle Sandwich" as it was known) plus polyurethane bushings, Koni's and stiff springs, a YA-code steering box, and with the suspension stiffened up, bump steer was a non-issue as far as tire wear and seat of the pants feel.

Crocie Sr. loaned me the Konis, the N2O kit, 1-3/8" sway bars and the 16" 3-piece wheels from his '64 GTO for the CC RSE. I'm sure Crocie Jr. still remembers this car, as he was about 16 yrs old at the time.

https://m.media-amazon.com/images/I/...aL._SL800_.jpg https://i.ebayimg.com/images/g/~04AA...I2-/s-l600.jpg

Tarl 10-10-2023 11:40 AM

I eventually pulled those spindles off my 66, as Scarebird said, the bumpsteer and especially turning radius are drawbacks even with the positive aspects of it (my lemans stopped almost as good with 1LE 12" rotors than with the current C5 brakes).

KEN CROCIE 10-10-2023 03:15 PM

H-O disc brake conversion kit P/Ns for 64-72 a body
tie rod ends : elgin es 2033 rl or sealed power 802-2033r
upper ball joint : 1268k or S/P 801-10268
lower ball joint: 277k or S/P 801-10277.
Lower ball joint gets turned down to 2.015",or .015" larger than stock for tight press fit.

CROCIE JR 10-10-2023 07:02 PM

hgerhartd I was 18 but sure acted younger and dumber I'm sure Hahahaha. Of course I remember that ride.! Good times


All times are GMT -4. The time now is 07:03 PM.