Imperial Homepage -> Repair -> Brakes ->Adjustment
Question from Philippe (1957):
I have an excessive travel of the pedal before brake apply. The brakes are efficient only in the last 1/3 of the travel (but the pedal don't touch the floor) with or w/o the brake booster and the distance between no brake and wheel locked is closed. I have adjust the master cylinder rod according to the FSM but I don't feel in security with all this "gap". Do you think I must lengthen the rod by adjusting the nut rod ? Or is it a problem of bleeding? I use silicone fluid.
Reply from Dick:
There should be just a little free travel of the pedal before it contacts and begins to move the piston in the master cylinder. No more than 1/2 cm, at most, as measured AT THE PEDAL, not at the rod itself. But there must be some free travel, so that the pressure relief port in the master cylinder is opened up after each use. If your pedal is too low, but otherwise everything is OK, it sounds to me that you just need to do a normal brake adjustment at the wheels. Your car doesn't have self adjusters. Just go through the normal adjustment at each wheel (tighten each wheel until it cannot be moved by hand, then back off 8 clicks), and see if that helps.
Question from Jeff (1958):
My brother and I just finished a total brake job on his 58 4dr and we are having a little trouble adjusting them properly. We have the manual and we have tried to follow the instructions but they seem to be too tight. Does anyone wiser then us have a sure fire method for adjusting them? The manual says to adjust them until they are so tight that the wheel locks then back the adjusters off till they spin freely. We did this but the brakes still seem too tight. Should we do the front or rear adjusters first? Thanks for any tips or hints you can offer.
I believe you have been bitten by the same problem I had. On the older Imperials and other Chrysler Corp. cars with the "Total Contact Brake System" the relined shoes are supposed to be ground down on a special machine which matches the internal diameter of the drum to that of the relined brake shoes. If the shoes are installed as is from a rebuilder, they are too large to allow proper operation, especially after some heat buildup in normal use.
You may be able to find someone in your area who still has one of the machines for doing this. I had a local dealer try to install relined shoes several years ago. He did not have the correct equipment to grind down the shoes. As a consequence, when I drove the car home, I smoked the brake linings. The car has hardly been driven since, and I am afraid I have warped the drums front and rear. You may have luck if you look for a clutch and brake service company which can work on farm tractor brakes. I understand that they are some of the only people left which may have the equipment.
The reason that the brake shoe grinding equipment is so rare now is that the EPA and OSHA made most of the dealers throw away the equipment because of asbestos dust particles being released when the grinding was under way. The danger is minimal if done correctly with the original dust shields in place. Another instance of government bureaucrats gone wild. I don't know if I can stand much more government protection!
The new brakes need those HARD FAST stops. Drums and new linings are rough and need to have this 'fuzz' worn off. This is called 'burnishing the brakes' I have made this a practice with every new brake job. I learned this in my first days of car ownership and maintenance.
It is the way to get the new brakes smoothed up and working up to their capability. The smoother the surfaces of drum and lining the more area that is touching, so it makes for better brakes.
If your brakes are over tight it may be that the shoes were relined with lining that is too thick. Chic got hold of some of these once too. He got them at a local auto parts and they had them ground to fit for him. Currently none of the brake linings we have been buying contain any asbestos. It has apparently been banned and recent relines don't have it. My guess is if these shoes were relined recently they would not have any asbestos. If they were NOS or NORS then that would be another story.
Did you put new springs and all new retaining hardware on the brakes? Are the wheel cylinders relatively new? Center plane brakes really love to stick. Weak brake springs may make your brakes shoes not return fully which might makes the brakes smoke and smell. By the way new brake lining generally smells for the first half dozen or so times you drive the car anyway even on late models. I wouldn't worry unless the brakes started to smoke as they really can catch fire if things get hot enough. Had it happen once on a '57 Imperial on an Interstate. Luckily didn't hurt the car much.
Question from Rex (1959):
How does one properly adjust those front brakes?
Reply from John:
The adjust you will see 2 adjusting cams on each front wheel. You will need a 7/16 socket & to tighten, you turn them in the direction of the FORWARD rotation of that wheel. The amount of travel on the adjuster is very little, less then a complete turn.
Question from Timothy (1960):
I've been busy over the last three weeks puttering away on a brake job on the sixty in my "spare" time (I have none hence 3 weeks for a 1.5 day job...). Here's the situation...No pedal! no matter how many time you pump it. We have replaced the front shoes and hoses, rebuild the front wheel cylinders, took apart the back drums and realized that the have already been done in the not to distant past and left it at that for the moment and adjusted everything, then gave it a try. When that didn't work we checked for leaks and air and decided that the master cylinder was leaking out the back. Yanked it and rebuilt it, reinstalled, rebled, readjusted, and still nothing. The car slows down and will sort of stop if it's not on high idle or pointed downhill. I have a new rear hose which I am still meaning to install but both BJ and I can't see how a hose that's not leaking could cause the problem.
After all that you have done, try going back and readjusting all the brake shoes. If you turned the adjusting cam in the wrong direction on just one shoe, then your brake pedal will go to the floor as you have indicated. Use a 7/16 inch six sided socket, of 3/8 drive to adjust the shoe cams. Six of the eight tighten in the forward direction of the wheels. The rearmost two, which are most frequently adjusted wrong, are tightened by turning in the reverse direction of the wheels. After you have properly adjusted the cams, that may solve the problem. But if it doesn't, then be sure to bleed the brakes in the proper order: right rear, left rear, right front lower, right front upper, left front lower, left front upper. Right and left are as you sit in the driver's seat of the car.
On my '62 it clearly says NOT to adjust the length of the pushrod between the booster and master cylinder. I only know because I switched boosters once, and was about to do just that when I read the notice. I agree that if its too long the cylinder won't be able to fully return , and if its too short there will be wasted motion before the cylinder starts to apply the brakes. I'd go back and double check the adjustment and maybe even double check the bleeding, that's a long distance to push an air bubble around. As far as the advice about the check valve in the master cylinder, that's also a very good thing to check and very easy too.
Question from Tony (1960):
How do you adjust the brakes on a 60?
The adjuster have 2 lugs per wheel that stick out through the back of the dust shield. You may also be able to adjust with a 7/16 offset box wrench, its just easier with a socket since you can just reach around instead of crawling underneath. Wearing safety glasses is a good idea just in case. The spring doesn't usually unhook from the opposite end but if it doesn't engage the hook, it does snap back with a lot of force. The removal part is no problem since you are just prying against the shoe & lifting the spring, at this point, the spring is not under much tension & will pop right off. When installing however, you are stretching the spring & caution should be used.
Basically the rear wheel adjusters turn CCW on the left and CW on the right as you look at the back of the wheel. The front brake adjusters BOTH turn the SAME direction as the wheel when the car moves forward. Spin the tire, tighten the adjuster until it stops the wheel, then untighten about a quarter turn.
Clarification from John:
One clarification on this. The adjusters all tighten in the same direction as the wheel is turning in the forward direction with the exception of the rear shoe on each rear wheel. These turn in the reverse direction. To sum up, first 3 on drivers side CCW, last one CW. Passenger side, first 3 CW last one CCW.
Before you adjust the brakes try stepping on the brake pedal a few times to center the brake shoes. Sounds also like you still have air in the system. I had a rough time getting my brake pedal up after the last brake job. It was a total brake job, lines, wheel cylinders, master, and hoses. I bench bled the master before I installed it. I went through the whole cycle of bleeding all wheel cylinders to no avail . Finally in disgust I re-bled the master at the line going in and to my surprise I got a hiss of air. The pedal came right up to the top.
I use a 7/16 swivel socket that has an open end wrench at the other end. What I did not read as part of the brake adjustment was to rotate the wheel in question the direction of travel, so must be off the ground, and adjust it as said prior, but remember that new lining as it seats will need another adjustment very soon, as when I do one, it needs another adjust in about 3 to 4 weeks, but I drive my 61 LeBaron about 20 to 30 thousand miles a year. I have several sets of spare brakes for it because I drive them so much. When I adjust them, I rotate the wheel in a forward motion on a jack stand and tighten till the wheel stops, then loosen about 1/32 of a turn, ever so slight, as I do not want to constantly be doing them.
Question from Gavin (1961):
How do you adjust the front brakes on a 61 Imperial. Mine are pulling to hard to the right. The shop manual does not go into detail about adjustment at all.
The biggest problem I've had with Imperial brakes is getting them adjusted properly. The front brakes adjust differently than the rear and most repair techs assume a Chrysler product will work the same as a GM or Ford. We all know that's a dangerous assumption on many levels! By 1963 Chrysler no longer used the dual-front brake cylinders, so the adjustment issues may no longer be an issue for you.
Put the car on jack that lifts both front wheels. Adjust the brake from the underside of the car: Loosen the retainer that keeps the adjustment screw from being adjusted. Tighten the adjustment screw until it stops the wheel from turning. Then loosen it slowly until the wheel turns freely, (just barely looser than a slight scrapping sound, which would be the brake shoe against the brake drum). Do that to both front wheels and try to be exact on the amount that you loosen each one so that they are equally loosened from the referenced "scrapping sound." Tighten the retainer to the adjustment screw, to keep the brakes at that setting. If it still grabs on one side, you probably have a damaged drum on the right side that must be removed and "turned" on a machine to be exactly round again.
There are two adjusting cams for each drum. One cam is for the forward shoe and one is for the rear. The cams have a 7/16 adjusting head. First loosen both cams and adjust one shoe at a time. To adjust the cam, tighten it down in the direction of forward rotation. I like to give the free wheel a spin then lock it up with the cam and wrench. Slowly loosen the cam in the opposite direction until there is no drag. The idea is to get it as close as possible without drag. When you are satisfied with the adjustment do the same for the other brake shoe. You may hear a slight scrapping due to imperfections in the drum. Adjust both wheels as close as possible to avoid front end pull.
There is no retainer nut to loosen on a 61, just the adjuster itself. This is adjusted with a 7/16 wrench. To tighten, turn the adjusters in the direction of the forward rotation of the wheels. The only exception to this is on the rear wheels, the rearmost shoes tighten opposite the forward rotation. Other possible cause of grabbing could be air in the lines.
Tips and Question from Joe (1975):
I have a '75 Chrysler w/ single piston floating calipers and 10" rear drums. I had to take the car off the road for about a year and while starting it up every few weeks I sometimes had a problem w/ one of the rear brakes sticking. After getting it back on the road, it had a nasty pull to the left under braking. I got rid of the sticking rear brake by backing off the adjusters a couple turns and my guess was that moving the car back and forth in it's parking space during that year off the road caused the adjusters to get cranked up too tightly. As the calipers on this car are bad for rusting, as in can't push the caliper piston back in it's bore, even though the brake line is is connected, and the cup seal around the piston looks fine, I swapped the calipers. (really must learn how to pop the piston out, hone the bore, and reassemble soon!) That took care of the brake pull, mostly and until recently.
My pull to the left came back, but now it was kind of intermittent. Based on some test driving it seemed to show up more after a hard stop and could have been related to turning corners w/ the brake on. That's what got me looking at the flex hoses, and while they sure don't look new, they are not kinked, frayed or wise worrisome in appearance. I may swap them in the interest of preventative maintenance.
Since it had been who know how long since a rear brake job, I pulled the back wheels and drums. Shoes getting old, but other wise looked ok. While the drums were off I put my foot on the brake a couple of times and released. Looking at the wheels I noticed at least three of the four shoes still in the extended position. I was thinking bad wheel cylinders, but a light tap on the shoes w/ the palm of my hand and they went back in place.
I am also going to lube up the metal to metal contact points on the floating calipers. Problem is that the FSM doesn't call out any lube in these areas, and I really don't ever remember seeing a real mechanic do it w/ this car.
Minor point - aren't late 60s/early 70 disk actually sliding caliper not floating caliper?? And therefore may require lubing??
I decided to tear one down for a closer look and what I found was a complete absence of grease between the shoe contact points and the backing plates. These points I'm sure require grease and like I said it's only been years since the last set of shoes went on. I cleaned up the backing plate, greased up the contact points, slapped the brakes back together and pumped the pedal. Imagine my surprise when the shoes on that side returned correctly. I repeated the procedure on the other side and went for a test drive. Brake pull disappeared again!
Reply from Jim:
No, No, No, self adjusters cannot over adjust a brake. (OK if you back up with HOT BRAKE DRUMS they will adjust to the new expanded size) But if you look at the adjuster mechanism it takes brake shoe movement (increased lining clearance) to cause the cable & lever to move the star wheel.
Stuck rear wheels? Don't forget the parking brake cable! I have had many stuck rear wheels tracked down to stuck cables. Disconnect the 'wheel' cables from the equalizer mechanism under the car Pull it out of its sheath and clean & lubricate (See lube info later)
>(really must learn how to pop the piston out, hone the bore, and reassemble soon!)
If these are the single piston type (it was the 75 right?) you don't HONE the bore. The best part of the design is that the seal rides against the PISTON. The non rusting, non corroding piston. Nothing to hone. IF the piston is crudded, clean it off or replace it. The hard part is really getting the DUST seal in place. BTW to remove you can pull the piston out CAREFULLY with a gripper tool (pliers?) or Put a block of wood where the pads go and blow a puff from an air gun into the brake fluid opening. DO NOT GET YOUR FINGERS IN THE WAY!! The piston will fly out VERY FAST & HARD. The block of wood should catch it and not damage it.
> I am also going to lube up the metal to metal contact points on the floating calipers.
YES YES YES do properly lube your brakes!
>Problem is that the FSM doesn't call out any lube in these areas,
Remember the FSM was written about how to service NEW cars. That's non-rusted, non-worn, still having their factory coated/plated parts NEW type of cars. Things need to be modified as they age.
> Minor point - aren't late 60s/early 70 disk actually sliding caliper not floating caliper?? And therefore may require lubing??
Same thing floating/sliding. some move on pins, some on tracks the main concept is that the outer pad is pressed against the rotor by the force of the piston pushing away from the other pad.
> I was thinking bad wheel cylinders, but a light tap on the shoes w/ >the palm of my hand and they went back in place.
Do still think them. Wheel cylinders are checked by pulling back the dust boots and seeing if fluid leaks out. If your were to disassemble the W/C to look for crud, heck just rebuild it. Actually if you are doing brakes on our older cars consider NEW W/Cs. They are not that much more than the price of a kit and you cant get new pistons as part of the kits anymore. (at least I cant find kits with pistons)
> I decided to tear one down for a closer look and what I found was a complete absence of grease between the shoe contact points >and the backing plates. These points I'm sure require grease and like I said it's only been years since the last set of shoes went on.
Ok here is the low down on brake lube. Do not get that "high temp" brake lube!!! Look at the can, it melts at what 400 degrees? How hot do you think your brakes get?? Here, do this experiment; Get some of that 'high temp' stuff and hold a match under it. It runs off like water. That is why you never see any white grease on the backing plates when you do your second brake job. Get some "anti seize" compound. This stuff looks like thick silver paint. It is applied with a brush and it melts at 2000 degrees! hold a match under it. IT STAYS IN PLACE. like you want a lube to do. (BTW if you are worried about getting any lube on the braking surface, which stuff has the better chance of running off??) I frequently find the anti seize on the contact points after my second brake jobs, many thousands of miles later.
Do lube every METAL TO METAL contact point. (No, don't put it on the lining) as noted above it WONT run off. Do put it on the parking brake cable. As the name implies, The cables wont ever seize or lock up again. Do use it on exhaust manifold nuts & contacts. as noted the exhaust it is nothing for it. IT stays put. Those pesky flanges spin right off next time. Do not put it on wheel nuts/bolts!! as noted they wont stay put. I did this once and was tightening up my wheels every week for a year.
As for brake squeaks, this is caused by the whole caliper assembly and the pads vibrating & rubbing in their mountings. You cannot stop them from vibrating (they are stopping the car for Gods sake) but putting the lube where they rub stops ALL the noise. The old squeaky wheel theory.
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