1960s 1968 DeVille Brake Pull to the left

[ChrisTabat]

I am a hobbyist restoring a 1968 DeVille convertible.  This forum has been a wealth of knowledge and support during this multi-year process and I have learned there are no dumb questions so here's another one:  A few years ago,  I completely rebuilt the brake system.  The only parts I didn't replace were the metal lines.  Upon completion,  the car stopped reliably but had a distinct pull to the left.  I knew I wasn't going to be driving it much because I would be tackling the body next,  figuring I'd fine-tune the brake adjustments when done.  Well, I'm back on the road, and adjusted the brakes carefully.    The first couple of stops were perfectly straight,  even without hands on the wheel.  As I drove more,  the pull to the left returned.  The car tracks straight when driving not under braking,  tires are brand-new.  I have replaced some suspension parts but not all,  but I'm not seeing any unusual play.  Brake fluid is up and no sign of leakage at the wheel cylinders.  It feels like an initial dart to the left when I first touch the brakes but then gets better as I apply more pressure.  Upon returning to our subdivision,  I tried a couple of harder stops, both forward in reverse,  and it now seems better again for the moment. The inconsistent nature of the issue has me a bit perplexed.  Do I just need to let them wear in a bit more, adjust further,  or is there something I may have overlooked? Rolling resistance on both fronts seems identical when on the lift. Thank you.

[Lexi]

Will leave speculation regarding your brake issue to a member who is more familiar with your model year of Cadillac than myself. That said, there are numerous potential causes for what you have described.

Of possible interest is that I recently acquired a 1968 Cadillac Master Parts List hard cover edition as reference material. Should you have any enquiries concerning OEM parts for your car, I would be happy to post what information I have from this volume, to assist. Welcome to the CLC Forum community. Clay/Lexi

[Big Fins]

Wondering if maybe a little speck of dirt from the master flaked off and is blocking the port to the R/F wheel from the proportioning valve.

[ChrisTabat]

I am getting RF braking - under hard braking it is locking up.   But I was thinking some dirt or maybe even a little bit of air still in the RF line could be causing this.   High on my list of solutions if it doesn't settle down is to re-bleed the brakes. 

[The Tassie Devil(le)]

Don't forget that when you were reversing and applying the brakes hard, you are actually performing the brake shoe adjustment which could be the reason why you have noticed improved braking going forward.

The Self adjusters on the rear only work when stopping backwards.

Your out of balance forward braking could be the result of the improper adjusting when changing parts.   Plus, a myriad of other problems like glazed linings, different tyre pressures, and extreme road camber.

I take it that your car has Disc Brakes on the front?   If they are drums, then the reversing and hitting the brakes will adjust all four brakes at the same time.

Bruce.  

[Jeff Rosansky CLC #28373]

I kind of had something similar with our 55.
Jack up the front and apply the brake slightly with a threaded rod against the seat.
What you want is something adjustable, but that won't move. Tighten the rod a turn and spin the wheels until you get some drag. See if you get drag out of one 1st before the other.

[ChrisTabat]

Thanks for the ideas.  The car has 4 wheel drum brakes.   I pulled the front wheels and drums yesterday,  checked that I didn't accidentally reverse the primary / secondary shoes on one of the wheels or install the wrong adjuster on the wrong side.  Appears that I had assembled everything correctly.  I sanded the linings,  chamfered the leading edges,  cleaned everything thoroughly and readjusted the brakes per the shop manual.  Interestingly,  I felt like I had similar drag on both fronts when rotating just the drums,  but after I put the wheels on and tightened the lugs,  the right front spun freely but the left front had some drag.   I pulled the RF again,  and put about 10 more clicks into the star adjuster to get similar drag with the wheels on.  Heading out of town for Easter so I didn't do another road test but hoping for better performance.   Based on the shop manual,  it sounds like it takes patience to get these right.    Will post another update later next week.   Thanks again for the ideas.

[TJ Hopland]

So you went through the whole process with the feeler gauges to make sure the anchor pin is in the right place?  That's one of those things that became non adjustable when we were just doing rear drums so people tend to forget that that was an adjustment point.

That bit about putting the wheel on making a change may be worth exploring.   I'm not sure what the setup is on these, does the drum slide over the studs/hub?  Or is it a more complex pressed assembly?

[ChrisTabat]

I did not check anything related to the anchor pin when I redid the brakes.  I'm not seeing anything in the manual regarding specs or that it is even adjustable.  But thank you for the suggestion - I will research further.    The studs are pressed into the hub and the drum slides over the studs/hub.   Interestingly,  the manual says to remove the entire drum/hub assembly, but since I replaced the drums with my brake project,  I'm able to simply removed the wheel,  then slide the drum off the studs with a few light taps with a hammer around the back edge of the drum.   Easier, faster and seems safer than pulling the bearing every time I want to go back in there.

At any rate,  I took my post-Easter test drive today.   While somewhat better,  it's not what I'd like yet with a noticeable left pull.   Very similar to last round:  started out good,  got worse,  then got better again. Per the shop manual,  I made several moderate stops from 30-40 mph, as well as several reverse stops.  We have a long, sweeping downhill right-hand curve near our home that requires light braking to negotiate safely.   The road is pitched left rather than crowned.  Always seem to notice the pull there even if it is braking better on flat surfaces.    Upon returning home,  I put the car up on the lift.   Both front wheels spun with similar resistance,  but the left drum was hotter to the touch than the right.  My next step will be to back off the left adjuster a few clicks.  As I understand the self-adjuster functionality,  it will tighten the brakes but not back them off if too tight.    It will be interesting to see if I can provoke a pull to the right by doing this. 

One other thing that I failed to mention to the point:   I have replacement of the left upper ball joint on my to-do list,  but have been procrastinating because it appears to be fairly major surgery,  requiring removal of upper control arm.   The car tracks well and has no pull, shimmy, or anything else suggesting a suspension issue.  The grease boot is ripped which is why I want to replace it, but didn't consider it a priority.  But could this be contributing to my problem? 

Thanks for all the ideas.

[The Tassie Devil(le)]

The studs are pressed into the hub and the drum slides over the studs/hub.   Interestingly,  the manual says to remove the entire drum/hub assembly, but since I replaced the drums with my brake project,  I'm able to simply removed the wheel,  then slide the drum off the studs with a few light taps with a hammer around the back edge of the drum.   Easier, faster and seems safer than pulling the bearing every time I want to go back in there.

Your problem could be right here.

These drums were never designed to be removeable, and it could be that when you are putting them back on, they are not correctly aligning.

The hubs are securely rivited to the drums so that when there is any machining of the drums required, the machined surface will always be true.   Loose drums cannot be securely held tight to the turning lathe.   The hub does this.

This is not so critical for the rear drums, as they don't do as much work as the front.   Plus, the front wheels are more susceptible to balance, or out of balance, than the rear.

Bruce.

[Michael Petti]

I had a similar problem only pull to the right. Won't bore you with whole story about botched brake job by a shop. My son and I fixed most of the issues but could not get rid of the pull. Like you when cold braked fine got warm and pulled, HARD, and the wheel was hot, like yours. Everything was new wheel cylinders, Master cylinder, rebuilt booster, hoses and shoes. The drums were turned and well in specs and had been switched left to right. Went to a shop specializing in classic cars. Upon inspection he said he noticed the brake shoes did not look right and thought the heat damaged the lining material causing more friction in that wheel. He changed the front shoes and bingo, problem solved. I had never seen that before and have done a lot to shoes over the years even using a propane torch to drive out brake fluid. Hope this helps. Please let us know what the solution turns out to be.

[ChrisTabat]

Thanks for the ideas.  Regarding the drum/hub as an assembly, my drums couldn't be turned any more and had to be replaced.  I only found drums that didn't include the hub, hence my approach of pressing the hub out of the drums.  I'm quite sure there weren't rivets to the hubs - I'm recalling having simply pressed them out.  If that is the source of some or all of my problem, I'm not sure what the solution is. 

Michael's situation sounds exactly like mine.  I will inspect the linings more closely.

I read another suggestion on a different forum saying that the shoe could be hanging up on a rough spot on the backing plate.  One thing I did not check when driving is whether braking more infrequently resulted in less pull.  If the shoes are hanging up, frequent braking could make it worse.

Lots of ideas to consider when I take it apart again, probably Tuesday.

Thanks everyone.  Will keep you posted .

[The Tassie Devil(le)]

Thanks for the ideas.  Regarding the drum/hub as an assembly, my drums couldn't be turned any more and had to be replaced.  I only found drums that didn't include the hub, hence my approach of pressing the hub out of the drums.  I'm quite sure there weren't rivets to the hubs - I'm recalling having simply pressed them out.  If that is the source of some or all of my problem, I'm not sure what the solution is.   

The drums are retained to the hub via a swaging of the Wheel Studs.

Different brands use different size swaging, and in most cases, the is a tool that is used to trim the swage before attempting to press off, and another tool to recreate the correct swaging when the new drum goes on.

The replacement drum has to be tight at the central hole, and when replacing drum, even new ones to a hub, I would be wanting to put a light skim over the complete unit to ensure that the Drum is running perfectly true.

By the way, were the replacement drums made overseas?   And have you spun the completed units to ensure that they are in fact true?

Bruce.

[ChrisTabat]

Drums are Raybestos,  purchased in 2017 as part of re-doing the entire brake system.  I then moved on body work so other than a few trips around the subdivision a few times a year to keep things loose,  the car hasn't been driven much in the last 8 years - maybe 100 miles.  Raybestos now markets their drums as being made in the US, Canada, Argentina or China,  so I really have no idea if they are Chinese or not.   

I must admit that you're stretching my understanding but the gist of what I'm getting from your advice is that the drum needs to seat perfectly on the hub and studs or it won't run true.   If by "spinning the completed units",  you mean spinning them on the car,  yes.  I have a lift and have spun the fronts with and without wheels/tires.   They both spin evenly, with similar resistance.   Other than the initial pull when applying the brakes,  the car drives and stops well.   No vibrations, pull, or shimmy.   It brakes smoothly other than the initial pull.  I have not removed the drum/hub and spun them on a standalone device.   However,  I did swap the front drums on my previous attempt to remedy the issue and it didn't seem to make a difference,  so I had kind of ruled out the drums as the culprit,  or even a contributing factor.

In my initial post I mentioned that it "felt like an initial dart to the left" followed by even braking.  I quantified that a bit yesterday by stopping moderately,  as I would in normal driving,  from about 30 mph,  without my hands on the steering wheel.   Upon initial application of the brakes,  the steering wheel rotates about 10 degrees left immediately,  then stays there for the remainder of the stop,  regardless of whether I maintain the same pressure on the brake pedal, increase or decrease.  It acts like the left brake is engaging a split second sooner than the right,  causing the initial dart,  then it brakes evenly. 

Thanks for the ideas.   I'll post more updates as I either resolve it or try things that don't work.  As mentioned earlier, I'm hoping to get some time tomorrow to back off the adjuster on the left front to see if I can either fix it or provoke a pull to the right. 

[The Tassie Devil(le)]

Don't forget that when braking on a "Normal" road, where the camber is curving to the Right gutter, there will always be a tendency for the car to slightly veer to the Right.   A bit like on the side of a hill.

If you can position the car, on the other side of the road, where the camber is to the Left side gutter, and perform the same braking, I wonder if it pulls to the right?

Camber does make a difference.

Lastly, I wonder if the vehicle is designed to appear to pull to the Left, to counteract the Camber falling to the Right.

I find when driving my LHD car in Australia, which we drive on the Left, I am sitting on the Left side, and if I am by myself, this driver weight is wanting to accentuate the car leaning to the left, especially when going around Right hand turns.   Fitting a rear Sway Bar to the car really helped negate the Left Droop on turns.

Bruce.

[ChrisTabat]

Latest update:  Last evening I removed the left front drum, and backed off the adjuster about 10 clicks.  I also cut away the torn upper ball joint boot that was rubbing on the drum.  I couldn't see how that could affect the braking,  but it wasn't serving any useful purpose since it was already torn.  Besides,  I don't even take the car out in the rain.   Removing the drum was a bit more difficult than in my 3 previous attempts which supports Bruce's theory that seating of the drum on the hub may be playing a part in my issues.    After reassembly,  the left front spun observably more easily than the right front. 

Took it for another test drive today,  somewhat expecting a pull to the right.  First several (6 or so) stops were straight,  followed by another 6 with a pronounced pull to the left again, starting out minor,  getting worse, then better.   However, the pull was short-lived relative to past test drives and less pronounced.  From that point on, any pull was barely perceptible.   Stops were pretty straight, with perhaps just a hint of a pull to left,  even with hands off the wheel - good enough that I wouldn't have noticed unless I was critically monitoring thm.   Upon returning home, front brake drums were comparably hot,  with the left perhaps just slightly hotter.   I didn't put it back up on the lift to do another spin test yet.

At this point,  I'm suspecting that the "spin test" is not a good indicator of brake balance - that is,  balanced spinning when on a lift doesn't correlate to balanced braking when the car is on the ground and in motion.    I'm going to drive it for a while and see if the issues progresses one way or another. 

Thanks again - stay tuned for future updates.

[Michael Petti]

Great! We will want to know.

[TJ Hopland]

10 clicks is a lot.  I usually find 2-4 makes a big difference.   I would think 10 would make the pedal go down a lot before much happened.

[ChrisTabat]

I agree.  I was fully expecting either more pedal travel,  a pull to the right,  or both.  I did replace the adjusters as part of my brake system rebuild.  I suppose it's possible the replacement adjusters have a much smaller travel-per-click than the original ones. 

Interestingly,  TJ's observation about 10 clicks being a lot rattled around in my brain.  I revisited the adjustment instructions from the shop manual - photo below.  (Not sure if they are readable.)  It says to tighten the adjusters so you can "just rotate the drum" with a 2' bar between the studs,  back off the adjuster 40 clicks,  and then drive it back and forth until the pedal travel is less than 1 3/4".   It also warns of erratic brake performance and how to address that.   I thought the 40 clicks was a misprint,  and was afraid to even try to drive the car.   But nothing like following the manual......  I'm going to drive it a while,  see if it stays settled down now.   Next step may be to back both way off and drive it per the manual.

[cadillacmike68]

Just a note. When my 1968 DVC still had drum brakes, I had the drums separated from the hubs for servicing with no issue. I have since put 1970 steering knuckles on it with disc brakes, 1970 rotors, 1968-76 calipers. It's a hybrid, but it has the strongest, most readily available parts.I got the ideas here in old threads where you can find my observations.

However,and this has happened a few times, the lower control arm bushings, if they can work loose and they can, the car will pull / lurch to one side or another. Check these, and if necessary have them tack welded in place. I've had my DVC for 27 years and have seen a lot. I won't say I've seen it all, because then the next time I take it out, something will happen...