Front axle - steering knuckles 1968-70 for disc brakes

[cadillacmike68]

My 1968's front disc rotors are developing what will be terminal failures. The outer races are starting to rotate in the hub. I got two rotors and neither fit.

It turns out that when the car was converted to disc, they used the parts from a 1970 Oldsmobile model 98. It works (worked), but the rotors for the 69-70 Olds B & C bodies are non-existent and every GM division did something different before 1971, so I need to get my car converted back to Cadillac parts with preferable the 1968-70 front axle (spindles / steering knuckles) to start.

The steering knuckle was the same from about 1961 to 1969, but what about the 2nd piece - the steering arm? does 1960 use the same steering arm?

I know that the 1970 went to a 1-piece steering knuckle and integrated arm. Will that fit on a 1968?

I'll also need a source for the 1969 (& perhaps 70-71) backing plates, and caliper brackets. I have 2 rotors and can get calipers if the ones I have do not fit.

This is one of the things about 1968s that I do not like as compared to 1969 & 1970.

[cadillacmike68]

From some more reading the 1970 steering knuckle combines 3 previously separate parts; the steering knuckle, steering arm and caliper support bracket.

Will the 1970 steering knuckles fit on a 1968?? That would simplify the entire process.

[Scot Minesinger]

Mike,

Here some pictures of an original steering knuckle out of a 32k mile 1970 Cadillac SDV just before reinstallation.  Hope this helps answer the question.

I would be on the lookout for some original 1968 Cadillac parts to make this right.  I worked on a 1969 Olds 98 restoration and the similarities between Cadillac and Olds front undercarriage in 1969 were about the same as Cadillac and Lincoln it appeared - completely different.

You know the deal 1967, front disc brakes optional on Eldorado, not available on RWD
1968 front disc brakes optional on RWD, standard on Eldorado
1969 and newer front disc brakes standard on all Cadillacs.

Hope that this all goes well for you,

Scot

[cadillacmike68]

Scot,

Yes, that's the one piece steering knuckle with the integrated steering arm and caliper bracket.

I would prefer to put the one piece 1970 steering knuckle on - if it fits. It is one piece instead of 3.

Does anyone know if it will fit?

Or, does anyone know if the tie rods interchange between 1968, 69 & 70. If they do, then it WILL fit. There are only three attachment points on the steering assembly to the rest of the car (not including the brake line!) They are the upper and lower ball joints and the tie rod ends. if those three places have the same dimensional planes & distances, then they will interchange.

Can anyone shed some light on this?

I did find this in a Cadillac parts manual:

6.230 TIE ROD, STEERING
66 All 7801849 10.75 TIE ROD. w!ball stud 2
67-70 Exc. EId 7801849 10.75 TIE ROD, w!ball stud 2
67-74 Eld 5699222 10.75 TIE ROD. w,/baIl stud 2

It does show a different tie rod end for 1968-69 vs 1970. So, I can get 1970 tie rod ends if needed.

The steering knuckle is the same from 61- 69 (excl 67-69 Eldo)with PN 3512224. 1970 and 71 are different because its a one piece item including the steering arm.

For the steering arm, it lists a different arm for 1968 disc vs drum. It might be because of a steering stop on the bottom of the 1968 arm.

6.103 ARM, STEERING KNUCKLE
65-69 (excl 65 Flt 75 & 67-69 Eldo) 1494327 LH and 1492326 LH
68 Disc: 1099365 RH or 1099364 LH, ARM

Upper control arms and ball joints are the same from 1961-70. Lower arms show a different part for 1970. I'll have to check a different source for lower ball joints. If they are the same then that's one more item suggesting the 1970 knuckle should fit the 1968 or 69 car.

Calipers and rotors are the same for all 3 years.

An all 1969 setup might save me from getting 2 tie rod ends, but a 1970 setup will cut down on the total number of items needed.

Still looking for some experts to weigh in.

[cadillacmike68]

I did end using the 1970 steering knuckles. I needed 1970 lower ball joints, 1970 outer tie rod ends and 1970 upper A arm camber eccentrics (but the upper ball joints were unchanged). It is a much stronger setup and I still have a full set of 1968-69 steering knuckles with disc brackets.

The lower ball joints pressed into the lower control arm. It was a Tight fit, but they are in there (and probably don't want to come out). Trouble free for 6 years now.

The only differences in these items from 1969 & earlier was the angle of the dangle on the conical shaped fitments!

GM must have determined that a different conical shape was better. All three attachment points have a different conical taper. Either that or a diabolical engineer decided to muck with future collectors.