I haven't done drum brakes ever but I'm faced with these drum brakes where
I'd just like to ask a couple of questions from those of you who have done
drum brakes before.
1. I released the parking brake from the cabin and screwed these 2-inch
long metric 8mm x 1.25mm threads bolts to pull the drum off the shoes.
2. After blowing the dust out (and not breathing it in), I could see that
the front shoe was worn down to about a millimeter or less (after 175K
miles), so I'm going to have to buy new shoes and replace them.
3. I measured the drum to be 2mm smaller than the maximum diameter:
4. Where the maximum diameter of 297mm was stamped on the drum itself:
5. It was hard to get the drum back on even with the parking brake released
from the cabin, so I had to use a mallet to bang it back on:
The main question is whether I'm supposed to *disconnect* the cable for the
parking brake when working on the drums, and particularly when I put the
new shoes on after I buy them.
Also, only one shoe is worn, and it's the front shoe, and it's been on
there for 175K miles, but I wonder if the shoes can be switched, so that
the front shoe is in the rear and the rear shoe is in the front, since they
wore so unevenly (sort of like rotating tires).
But mainly I'm not sure what the procedure is for the parking brake cable.
Can you advise?
On Sunday, January 7, 2018 at 9:02:24 PM UTC-10, Mad Roger wrote:
It depends on the cable. Some have a spring that keeps the cable end firmly
in place. Those can be tough to put back on. In that case, I'd leave the c
able attached. The parking brake arm is held on with a clip so you really d
on't have to detach it. Just clip it on the new shoe with the cable attache
Your photos don't show any spring attached so it could just fall off when y
ou detach the arm from the shoe. Make sure you take a lot of pictures. I wa
s working on some brakes a couple of weeks ago and just blanked out on wher
e to attach a spring. Your brake looks pretty simple so that's a good thing
It's normal to have one shoe worn more than the other - they were designed
that way. Brake shoes are cheap, so replace both. A hardware kit with new c
lips and springs are nice if you can get it. Good luck!
It appears the one shoe is unevenly worn. Could be a bad cylinder or
another stuck part such as the adjuster. Check them and replace/repair
Maximum diameter of what? Are you aware of the adjusters? Each side has
one and it sits under the cylinder behind the hub. You can see it in
It's job is to keep the shoes against the drum and is automatically
adjusted when the parking brake is used. Often, this is the reason why
drums are difficult to remove. They are adjusted from the other side
through an opening using an adjustment tool and often need to be
loosened in order to remove the drum. They also need to be tightened
after you replaced the shoes and re-install the drum. Retract them and
your diameter will be less than the drum.
Back to the adjuster.
The parking brake cable doesn't need to be removed, assuming it's
functioning properly. Just ensure the parking brake is not engage when
replacing shoes. The parking brake assembly will be removed when the
shoes are replaced.
Much depends on the vehicle. Many shoes are identical and it doesn't
matter if they are placed in front or rear. Others are specific and
require proper position and seating. In your case, the shoes appear to
be the same but that wear is something I wouldn't simply "rotate" with
the other side. One side wearing more than the other is not normal and
should be checked, repaired/replaced then install new shoes with the
proper even thickness.
Thanks for your help as this is my first set of drum brakes ever.
This is a side view closeup of the front unevenly worn shoe:
I had been, for years, looking through the peep hole, but that showed a lot
of meat on the shoes. You really have to remove the drum to see the actual
shoe, so, after 175K miles on the same shoes, I finally removed the drum
and noticed that the front show lower end, is worn tapering to the middle,
while the rest of the shoes are just fine.
Thanks for that advice.
The cylinder seems to not be leaking but that's all I can tell.
There have been no unusual braking events so I'm not debugging anything.
I googled a bit, and it seems "normal" for Toyota 4Runner rear brake shoes
to wear most in the front show on the bottom half. Something to do with the
geometry. I can't complain, as the shoes definitely are original so 20
years is a long time for a brake shoe to finally wear out.
In that photo you can see that the inside of the drum has a molded in
maximum diameter of 297mm. I assume that means the maximum diameter.
My calipers are in US measurements where 11.615 inches converts to about
So I assume the drum is good by 2mm in thickness.
Yes. This vehicle adjusts automatically when you brake in reverse, so I've
never dealt with them - but I am going to have to back them out for sure
when I put the new brake shoes on.
You can see the adjuster here:
I'm just not sure what we're supposed to do about the parking brake cable
linkages. I don't know yet if they have to be disconnected when putting in
new brake shoes.
You can see the parking brake cable here:
I understand what you're saying, which is that the brake shoes may be
"wedged" against the drum, but I had the vehicle in the air and the parking
brake off, so, any wedging shouldn't be too strong.
This is a closeup of the parking brake cable connection to the shoes:
As it was, putting the two 2-inch long 8mmx1.25 bolts in the two holes for
the purpose pushed the drum off easily. I had to squish the shoes a bit to
get the drum back on - and if necessary - I would have twisted the adjuster
- but I didn't need to.
Oh. OK. The parking brake seems to be a thick black cable that comes in at
the bottom of these shoes.
I think I'll replace the shoes, but since they lasted 20 years, I was just
wondering if "rotating" them every two or three or five years would have
extended the life of them.
It's a late 90's 4Runner.
They don't always have to leak. I've had a few that were stuck due to
some rust within the cylinder. I just replaced them since they were
cheap back in the days of yore. Though, I did take one apart and freed
it up with some cleaning. It appeared to work fine after that.
I can't speak for normality but I just find it odd that it would wear
like that when there isn't a bad part. Usually, I would see one show
worn more so than the other, but never a tapered wear.
Most adjusters work with the emergency/parking brake. Though, many
people rarely, if ever, use the parking brake and those adjusters can
rust up and stop pushing the shoe against the drum.
I have worked on many drum brakes and I have never had to remove a
parking brake cable. The cable is attached to the metal assembly and
that will just hang on the cable when you remove it and replace the
shoes. Though, if it's easy to remove and reattach, then there's no harm
in doing so.
Agreed. There should be a slight drag and minor friction when you turn
the drum, but never should be too tight where it's difficult to remove
Yes, attached to the metal assembly which turns that adjuster.
All I can say is I've never "rotated" brake shoes, since IMO, they were
cheap when I used to work on many cars. I can sympathize when only one
shoe is worn while the other(s) have ample thickness. I hate to see such
waste. The choice is yours since it appears the shoes are the same on
each side, you could simply swap them and ensure that drag and minor
friction partake when you reinstall the drum. Honestly, if it were me in
my youth as a poor teen working on my own car, that's what I would do.
But now that I'm a wealthy millionaire (that's tough to say without
laughing) Ok, now that I'm financially stable, I would just buy them and
install. Since you have to remove all the hardware anyway, installing
new shoes would be the best option.
Only vehicles with "twin leading shoe" brakes use the same shoe front
and back - and I'm not aware of ANY vehicle built with twin leading
shoe brakes since the early seventies - and then only British
vehicles. The leading and trailing shoe are generally of different
lengths as well as often different friction materials.
Actually it IS common - and considered normal, for the "leading shoe"
to wear differently than the "trailing shoe" on a servo type (self
energizing) brake system - which virtually all recent (modern) drum
brake systems are. the leading shoe contacts the drum, and the drag
(friction) on that shoe rotates the shoe through the linkage between
shoes, forcing the trailing shoe more firmly in contact with the drum.
This enhances the brake action beyond what would be possible strictly
by the hydraulic force from the wheel cyls.
It generally unhooks from the activbation lever connected to the
brake shoes. On soime cars the lever unhooks easily from the shoe and
does not NEED to be disconnected from the cable
Again - I would ADVISE you (the OP) to have a mechanic properly
repair the brakes.
On Monday, January 8, 2018 at 9:10:54 AM UTC-10, Mad Roger wrote:
Drum brakes in the rear work perfectly fine for most vehicles because most
of the braking is done with the front brakes. The reason 4 wheel disks are
popular are mostly because people want it because it sounds cool. The probl
em with disk brakes is that it's less effective as parking brakes. Some rea
r disk brake systems will have an integrated brake drum and separate mechan
ical drum brake system to use as a parking brake.
You should know that the starwheel adjuster will have left and right parts
that are not interchangeable. One side will have a right handed thread.
To set the initial clearance, start with the adjuster completely in, then t
urn it out a couple of turns. If the drum slips on easily, turn the wheel o
ut more turns until you feel some resistance. Once you get the drum on, ste
p on the brake to center the shoes. You might then have to adjust the clear
ance some more. Set the shoe clearance until you hear some light brushing w
hen turning the drum.
The parking brake is adjustable. This was usually done with a threaded
sleeve over a threaded stud mounted between the two shoes at either
the top or bottom. On the threaded sleeve is a toothed "wheel" which
is used to turn the sleeve from the inside of the brake mount plate
when the brake drum is on. There is a special tool for this, which
resembles a small pry bar. You can probably find or make something to
Before putting the drum on, turn the sleeve in to shorten the link
between the two brake shoes. The brake drum should then slide right
on. Put on the tire and tighten the lugs to hold the drum properly in
position. From under the car access the slot behind the toothed wheel,
and using the adjustment tool turn it to lengthen the adjuster until
the tire can no longer be rotated by hand. Then back the adjuster off
until the tire can just be rotated easily.
BTW, make sure that the longer of the new brake shoes is on the BACK
for each wheel.
Someone who thinks logically provides
a nice contrast to the real world.
I picked up at Harbor Freight a bunch of brake tools, one an all purpose
foot-long pliers, the others the special-purpose spring tool so I should be
ok on tools unless there is a Toyota-specific tool required (which I don't
think there is).
That makes a lot of sense, so I will do that when I put the new shoes back
on. I probably should have turned the toothed wheel a few clicks even when
I inspected it and put it back on, as it was a bit tight getting the drum
back on. I had to use a mallet.
This makes a lot of sense!
It would adjust the brakes to the minimum, where the automatic backing up
in reverse will fine tune it, I guess.
Ah. That means that the two shoes are NOT identical!
That negates the idea of "rotating" them every few years like we do tires
every five thousand miles to get more even wear out of them over time.
That is the SERVICE BRAKE adjustment - the parking brake adjustment
is separate - on the cable - and on the VAST majority of vehicles on
the road today the parking brake is totally self adjusting, as is the
service brake. Different schemes are used on different vehicles and
understanding how it is supposed to work is CRUCIAL to doing a safe
and effective repair.
On Monday, January 8, 2018 at 1:11:54 PM UTC-6, Mad Roger wrote:
I once owned a 1950 Ford car. One day when I was driving and one of the rig
ht front wheel brake shoes came loose. That caused the car to make a sharp
right hand swerve to the right, RIGHT NOW! Good idea is to check the brakes
and brake fluid once in a while. Sometimes it is more important to STOP th
an keep on going.
On Mon, 08 Jan 2018 17:06:20 -0500,
Clare Snyder wrote:
You're correct that the handbrake is what adjusts the drums (I was wrong in
assuming it was the action of braking in reverse).
People seem to say that the "bellcrank" needs replacing, so I dug into the
terminology to find this parts diagram.
I think the bellcrank are the funny shaped pieces.
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