I'm at a Braking Point

[packick]

I just completed a brake job on my ’55 Century.  New lining all around, the linings were arced to the drums, and the drums were within specs.  I also installed 3 new brake hoses, 4 new wheel cylinders, and adjusted the eccentrics and, obviously, the brake shoes.  After reassembly, I took the car for a test drive and the brakes pulled to the LEFT.

 

So, I pulled off both front brake drums and all looked OK, nothing installed wrong.  Next I decided to switch the front brake drums, shoes and springs (left-to-right, right-to-left), readjusted the eccentrics and readjusted the brakes.  Another test drive.  This time the brakes pulled to the RIGHT.   

 

By switching the drums, shoes, and springs on the front, and having the car then pull to the other direction, I think I can rule out a bad or clogged brake line, or a bad wheel cylinder.

 

I am stumped.  What next step would you recommend to debug this problem?  I can switch the drums to see if one of the drums is the problem, but I am concerned that since the shoes were arced to each drum switching them would not let the shoes sit correctly in the different drum.

Edited March 11, 2017 by packick (see edit history)

[NTX5467]

I might suggest you NOT do any panic or "hard" stops until you've bedded-in the linings.  That means gradually doing more aggressive stops . . . from gentle to lightly moderate to moderate to hard moderate levels of stopping from about 40mph until the linings have enough heat to cook out the resins in the linings.  This is NOT a "one time" procedure, but over a few days.  The OTHER issue could be that the one drum has a rougher surface texture than the other one does, which "grabs" harder per psi of brake line pressure.

 

I know that on disc brakes, the surface texture can be critical after a rotor has been resurfaced.  If the non-directional polish is not applied to a normal cut, then grabbing and early fading can occur.  PLUS brake pull!  I didn't want to spend the extra money for Delco rotors, so I got an auto supply brand with a "satin" finish.  The first time I applied them a little heavy, from 40mph to 20mph, they were spongy.  After a few more, I smelled them, so I went to were I was going and parked the car.  After it cooled down, the brakes felt a little better than at first.  I drove normally.  The next day, a few more harder stops.  More "heat" smell, but it took more to get to that.  I parked the car and let it all cool down.  Next day, repeat.  With each cycle, it took longer to get to the fade point and less smell, plus a firmer pedal feel.  After another time or two, the "break-in" seemed to have stabilized and things were normal.

 

Once, we had a quality control guy who'd take a fresh brake job out and do hard stops with the vehicle.  Brake pull, once to the left, another time to the right, with no consistency.  He was expecting the "green" linings to operate as if they were fully broken-in, which will not happen, especially back in the 1990s.  I've recently seen some brake lining brands which note "no break-in needed", so I guess they're "cooking" them before shipment?

 

It's good that you got everything "fitted" AND found somebody that can still do that, but "green" linings still need to be broken-in via "heat" before any panic or hard stops are attempted.  Normal stops should be no issue, though.

 

NTX5467

[JohnD1956]

are you adjusting the brakes by the number of clicks of the adjusters, or the feel of the brake drag when spinning the tires? If by the # of clicks, I wonder if the arcing process results in the one set tighter than the other?   You might try loosening the adjuster on the side that's pulling.

[Guest]

The adjustment advice that JohnD1956 gives is exactly what is suggested in all my brake books right back to the teens.  You don't tighten the loose side you always loosen the tight side.  NTX5467 is also correct that you need to break in your new brakes.  Gently for a few hundred stops over a few days and miles with time to cool off between drives.  One real hard panic stop can ruin linings and/or drums if they haven't been run properly.

[old-tank]

...and adjust every100 miles until stable.

Be sure lining material is the same.

Be sure short linings are to the front on all wheels.

[Guest]

Amen to that.  Check and double check.  I have driven my car 400,000 + miles since I started driving it.  I have changed the brake linings enough times that I thought I could do it blindfolded.  About two relines ago the job was not a success.  I checked everything three or four times.  On a forum a man from Australia mentioned that on Midland Steeldrauluc shoes with one rib that rib is off center.  If the shoe is on the wrong side the shoe twists and binds.  I had never noticed that 1/8th of a difference in five relines.  I am not as smart as I believed.

Good Luck

Edited March 11, 2017 by Guest (see edit history)

[packick]

 In reply to your questions:

 

- I failed to mention in my initial posting that I DID what NTX5467 suggested and applied the brakes a little hard going from about 30mph to stop a dozen times or so.  This straightened out the braking as the shoes were warm/hot, but the next time I drove the car when the brakes were cold they again pulled to the left.

 

- I usually adjust the brakes initially by clicks to get them close, but then fine tune them by listening to the drag on the shoes.  I then fine-tune the adjustment so that there is a bit of drag.as I rotate the drum.

 

I am going to try one last test.  I am going to switch the drums only (i.e., not the shoes) and see what happens.  There is always the possibility that even though the shoes and drums were labeled RF and LF, the shop may have arced the wrong shoes to the wrong drum.  Who knows.  If it still pulls one way or the other after that test, then I will do as JohnD1956 suggests and loosen the side that's pulling, and then put many miles on them hoping they will straighten themselves out.

 

Thanks for the help.

[Smartin]

All else equal, the drums are what I would look at.  Maybe a fresh turn to make the surfaces the same.

[old-tank]

2 hours ago, packick said:

This straightened out the braking as the shoes were warm/hot, but the next time I drove the car when the brakes were cold they again pulled to the left.

Look for grease contamination on the shoes.  Some of this new brake shoe material seems to absorb moisture making the first few stops squirrelly.  In addition to drive and adjust, make a lot of stops in reverse.

[buick5563]

Also, I believe the manual says 12 clicks or something like that. I have found that 8 is the magic number for me.

[packick]

Old-Tank:  Thanks for the tip.  I hadn't thought about stopping in the reverse direction.  I will add that to my list of tests.

 

Buick5563:  I agree with you.  About 7-8 clicks usually works for me too.  Thanks.

[NTX5467]

Remember, too, that in order to "heat" the linings, it doesn't take a hard stop to do that, but more light to moderate applications of an extended time can work better on new linings.  Say from 70 to 50 over about 5-10 seconds, then continue driving a few more miles.  I recently had the f/r pads replaced on my '05 Impala.  The rotors were surfaced and rather than the swirl polish, he did an alternate procedure which might work better . . . using a wide piece of rough sandpaper held against the rotating rotor for a consistent circular pattern, which took out the cutter marks (think phonograph record grooves) for a consistent surface for the pads to wear against.  A similar procedure could also be done on the drum's inner surface after the cuts.

 

So, on my way to the farm, there is an off-ramp that is long enough for a gradual slow-down to the access road.  The gradual method works there and it's about 2 miles to the farm from there.  Each day, a little better until things felt more stabilized after about a week (once per day).  Everybody has their own "best way" of doing this.  I prefer things a little more gradual, personally.  End result is that as with pistons, rings, and cylinder walls, all must "make friends" and work together for best results.

 

TWO FYIs on brake frictions.  ONE is that friction materials are being reformulated (more recent production) to reduce the level of copper to basically "zero".  Seems the brake dust contains copper which has been associated with water stream pollution from roadway run-off.  This is probably one reason why "ceramic" compounds are being added to brake frictions, I suspect.  TWO is the "Edge Codes" stamped on the lining segments.  This is the identifying "birth certificate" for the friction material.  It identifies the maker of the friction material, the batch and date, but the most important (to me) is the two-letter code at the end of that alphanumeric string.  These letters designate the cold and hot effectiveness of the friction material, i.e., how much braking power.  The highest letter is "G", but that's generally racing-use product.  The pads for my Impala were "FF", which is the next-highest level.  I believe the lowest level is "C"?  In some cases, as in some of the 9C1 police pads I put on my Camaro, I could feel them bite more as they heated up with no increase in pedal pressure (they would probably nave a EF code, but if they had an FE code, they'd work well when dead cold and seem to lose some power as they got hot).    A related thing is that a large and wide drum brake might work well with "CC", but a smaller and narrower drum with "DD" frictions might perform equally in 90% of applications for the same/similar weight vehicle. . . in theory.

 

Thanks for the updates and please keep us posted.

 

NTX5467

[Beemon]

4 hours ago, buick5563 said:

Also, I believe the manual says 12 clicks or something like that. I have found that 8 is the magic number for me.

When I had manual adjust shoes, I always did 4-5 clicks. Now I'm thinking it was too tight. The 56 shop manual says 25 clicks... lol

[old-tank]

2 hours ago, Beemon said:

When I had manual adjust shoes, I always did 4-5 clicks. Now I'm thinking it was too tight. The 56 shop manual says 25 clicks... lol

Probably do no less than 6 clicks from "tight enough to barely be able to turn".  Shoes will expand when hot (some more than others).

[NTX5467]

Might the "number of clicks" be related to the thickness of the lining AND the inside diameter of the drum?  More clicks if the drum is worn and/or refinished to the stated max diameter?  Fewer clicks if the brake show linings are thicker to allow for arcing/grinding to match the drum diameter? Or what the Buick service manual mentions IF everything is NEW and to factory (unused/low mileage) specs?

 

I might suggest the use of an inside/outside caliper to do the adjustment with rather than "the sound/drag" method.  In the case of the latter, it would seem that a few clicks LOOSER than just barely hearing rubbing might be best.  To tight and the friction will unnecessarily heat the linings, which could lead to premature "fade" in some cases PLUS decreased fuel economy and other things related to "chassis drag" on powertrain performance.

 

NTX5467.

[packick]

NTX5467:

 

In my uneducated opinion I don't think the thickness of the lining and/or the diameter of the inside of the drum would make a difference.  Assuming you tighten the adjusting wheel so that the brakes rest against the drum so that it is hard to turn, then back off 6-7 clicks, the linings would still be the same distance away from the drum whether new or worn.  Or am I missing something here?

[Caballero2]

I don't know for certain, but on the '57 there is a major adjustment involving the brake shoe anchor pin. This aligns the arc centers of the shoes to the drum center.  This must be done whenever any extensive break disassembly has occurred.  The procedure is explained in the service manual.  I wonder if the '55 is the same or similar?

[packick]

Caballero2:

 

Yes, the '55 has this adjustment too.  In my initial post I refer to the anchor pin adjustment as adjusting the eccentrics.  That's the term I use since I have seen that term used in other manuals.  I did make this adjustment following the shop manual's instructions both times, when I did the initial brake job and again when I switched the shoes to the opposite sides.

[JZRIV]

When you have drums off take marker like a sharpie and draw a series of horizontal lines on the shoes maybe 2" apart.  This might help determine each shoes effective contact pattern after several cycles.  

[NTX5467]

I'll admit that nobody I ever saw do drum brake adjustments (back when) used the "number of clicks" criteria in doing manual brake adjustments.  What they did do was get the adjustment tight enough to lock the wheel from spinning, then back off the adjustment until the wheel would spin and then additionally until the "just barely touch" sound was heard.  Then probably another amount (learned by experience) for good measure.  IF the adjustment was "good", braking would be quick and firm "at the top of the pedal" travel.  End result, whether by clicks, the swing of the adjusting spoon, or feel, a particular clearance between the brake linings and the drum friction surface would result.  The inside/outside caliper (mentioned) takes the guess-work out of the situation, but THAT tool was not known about at that time.  Replacing the plug in the adjustment hole was the last step in the process.  Later, GM started to put knockouts in the brake drums themselves rather than in the backing plate.  And, of course, self-adjusters had become common by that time.

 

SOMETIMES . . . the perceived need for a lining adjustment could be removed by blowing out the accumulated brake dust from the drums!  Such accumulated dust removal "cleaned things up" such that quick and efficient brake application returned.  Now, doing this in modern times would NOT be approved for environmental reasons.  Just ONE drum being cleaned would dust an entire mechanic shop, for example, so adequate ventilation would be needed.  In modern times, you'd need to probably remove the drum, use spray brake cleaner with an appropriate "catch pan", then dispose of the "catchings" in an appropriate manner consistent with good environmental practice.

 

Perhaps the "number of clicks" variations mentioned was due to the thread pitch on the adjuster parts changing over time?  Fine thread vs. not-so-fine thread pitch?  I always figured the thread pitch was SAE-specified, or similar?

 

NTX5467

[60FlatTop]

Where did the new shoes come from? Are they NOS, New Stock, non-asbestos, what grade (my provider has three, all the same). Are they riveted or bonded? Are the springs new? Were the wheel cylinders opened and inspected. Why did you adjust the eccentric as part of the job? Is there a dab of lubricant on the backing plate where the shoes rest? At any time did anyone have to clean a shoe? If new lining material was used is it measured in inches or millimeters and is it all the same?

 

When I did the rear brakes on my '60 I couldn't get the drum back on. I called the brake shop and they told me a bunch of BS about the anchor pin and anything else they could think of while holding the phone and staring at the ceiling. I knew I did my part right so I brought the whole setup back and plunked it down on their counter. The "expert" looked it all over and went to his books. He was quite apologetic when he said "Oh, yours is the 3/16 lining, we put 1/4" on. Let me fix that." Grrrrrrr.

 

I went home with the thinner lings and things were fine after that. Along with the other variables the brake shop may be converting MM to inches in their head.

 

When you do everything right and know it, double check the other guy.

Bernie

[packick]

Bernie:

 

The shoes are new and most likely non-asbestos.  I have no idea what grade they are, They are bonded, not riveted, and the brake springs are the same ones that were on the car before I started the brake job.  (Note that before I started the brake job there was no pulling to the left or right.  The shoes were just worn.)  The lining is all the same on all 4 wheels done by the same shop at the same time, however one thing I want to do is measure the length of the linings, especially on the primary shoes, to make sure they are all the same length.  I assume that if the lining on one shoe is longer than the corresponding shoe on the other side then it might have more braking power and thus cause pulling.  

 

Update:  Recall that the pulling went from the LEFT side to the RIGHT side when I switched the shoes, springs and drums to the opposite sides. Yesterday I switched the brake drums, but not the shoes and springs, back to the original sides.  After a test drive there was still pulling to the RIGHT.  So, now that the drums are back to where they were when it pulled to the LEFT, I am now convinced that the shoes on the right side are causing the pulling.  That's why I want to measure the lining lengths.  Any other thoughts?

[Ben Bruce aka First Born]

Don't you just love GREMLINS.?

 

  Ben

[Daves1940Buick56S]

Joe

I think you are closing in on it. Make sure the shoes are the same for each side, primary and secondary. Short lining to front, long to rear. If that's good, then I'd try a couple of clicks looser on the tight (right) side.

 

Cheers, Dave

[packick]

Another Update:

 

I pulled the front drums off again for the purpose of measuring the brake linings on each wheel.  As you will recall the car pulls to the right after switching the shoes from the left side to the right side.   Here is what I measured:

 

  Primary Left Shoe - Length 10-3/4” ; Width 2-1/4” ; Thickness ¼”

Primary Right Shoe - Length 10-5/8” ; Width 2-1/4” ; Thickness ¼”

 

  Secondary Left Shoe - Length 12-3/8” ; Width 2-1/4” ; Thickness ¼”

Secondary Right Shoe - Length 12-5/8” ; Width 2-1/4” ; Thickness ¼”

 

Here’s what the Shop Manual specifies:

 

     Length – Not specified

       Width – 2-1/4” Primary and Secondary shoes

Thickness – 0.187” Primary and Secondary shoes

 

I am not too concerned with the thickness difference between the shop manual specifications and my shoes, but look at the lengths.   I don’t know if the extra ½” length on the Secondary Right Shoe, and/or the extra 1/4" length on the Primary Left Shoe would cause pulling to the right side or not.  Would that small difference in length cause pulling?

Edited March 14, 2017 by packick
Added more detail. (see edit history)

[old-tank]

5 minutes ago, packick said:

Would that small difference in length cause pulling?

No.  New shoes, even those arced to fit  will usually not have the ends of the shoes with a contact pattern until used for awhile.  The only thing thicker shoes may cause is the adjustment will not close enough to get the drum on.  And sometimes the brake places put on thicker shoes if the drums are worn.  Most wear limits on drums is 0.060.  0.187(manual spec) plus 0.060 = 0.247 (there's the 1/4 inch!).

Before assembly again scuff the drum and shoes with coarse sand paper and drive carefully.  If you have to take it apart again take it back to the brake place. Or if measuring with  a brake caliper shows all drums are close to the same size, swap the rear shoes to the front.

[packick]

Old-Tank et. al.:

 

Good news.  I did what Old-Tank suggested and "scuffed up" both the linings and drums with 80 grit sand paper.  I always use sand paper on the shoes and drums when I do a brake job but I guess I was using too fine a grit (150) to really do any serious scuffing.  I took the car for a test drive and now it sorta drifts to the right when the brakes are first applied, then straighten out for the rest of the stop.  I think, with miles, this too will get better.  At least it is not pulling to the right.

 

Thanks to all respondents for the help and advice.

[NTX5467]

In theory, ANY additional length of friction material can cause an imbalance in the system.

 

At this point in time, rather than get another set of brake shoes, it might be possible to "fix" the existing shoes with a cut-off wheel or a band saw.  Cut the longer shoes to match the shorter shoes.  First with a cut at one or both ends to result in the friction length being the same.  Then a cut parallel to the brake shoe base to remove the friction material to a lower level than the main friction surface.  Dress/smooth any rough edges on the remaining friction material.

 

What about "staggering" the shoes, such that EACH side has one longer-than-the-other one-like-it-brake shoe rather than one side with both longer shoes?  Might that balance out the friction area between the sides?

 

Just curious . . . what about the condition of the front suspension bushings and such?

 

NTX5467

[old-tank]

48 minutes ago, NTX5467 said:

Just curious . . . what about the condition of the front suspension bushings and such?

If the toe is set toe-out you can get pulling.

[packick]

I agree that cutting the longer shoes down is probably one solution.  But looking at the measurements of the shoes' linings, if you add up the measurements of both the primary and secondary linings for each side, you get 23.125" shoe lining length for the left side, and 23.250" shoe lining length for the right side.  That means the right side has a 1/8" longer shoe lining surface than the left side.  Is that really enough to start cutting them down?

 

I had also thought about staggering the shoes on the front but if you look at the measurements, moving the shoes around I still would have one side's lining longer than the other.  I could probably move some rear shoes up to the front to even out each side, but I am afraid that would open up a brand new can of worms.

 

As far as alignment goes, prior to doing the brake job I had to replace the rear main seal.  That job totally screwed up the alignment so I took the car to an alignment shop and had them set the alignment to specs.  So I am sure the alignment is spot-on.  And prior to the brake job, the car stopped dead straight.

[EmTee]

6 hours ago, packick said:

Would that small difference in length cause pulling?

 

It might, if that part of the shoe is contacting the drum first...

[Guest]

I would suggest that whoever relined your shoes or whoever supplied them should give you a matched set and whoever arced you shoes should arc your new ones because he/she should have noticed that they weren't a set. 

With my problem I may have played around and fussed over poor braking but it was my fault that I didn't notice the web in the shoe was offset.  But your problem was caused by others.  Too bad you can't get reimbursed for your labour.

[60FlatTop]

My Wife is always friendly and pleasant even when confronted with the most bumbling mistakes by people providing her with services. You know how they say opposites attract, well they sure do in our case.

 

I make a real effort to do things right. If your car came to me for service you would probably notice all the window garnish molding trim screws were horizontally parallel when it left. And I would double check to be sure I spelled your name right.

 

Now, if you do take the shoes back, show the guy the differences in length and ask him why. If he gives you some lame answer don't forget, a reply of "Did you miss Sesame Street the day they did "Just Like"?" comes in handy soooooo many times. Even if it doesn't resolve anything it makes you smile inside. I'm smiling now!

Bernie

Edited March 15, 2017 by 60FlatTop (see edit history)

[packick]

One other question.  I know that on most cars there are different colored brake springs (red, yellow, etc.).  Both of my springs look exactly the same as far as length, coil diameter, and the spring metal diameter.  It looks, however, that someone has slathered white paint on two of them . . . it doesn't look like the spring manufacturer did this.  Does the '55 Buick have different colored springs for the primary and secondary shoes and, if so, which color goes on the primary shoe and which color goes on the secondary shoe? 

[Beemon]

The springs should be the same for both shoes. 

[EmTee]

For Bernie (and I'm smiling now)... 

 

https://www.youtube.com/watch?v=FClGhto1vIg

 

[60FlatTop]

"Restraint is one of my least recognized attributes"

Bernie

[NTX5467]

"Slathered paint"?  Might have been a line inspector that checked to ensure the springs were installed on the brake assy?  The paint was there to show that he inspected them (as with other things on the vehicle which line inspectors inspect)?

 

NTX5467