Fun and games with Bendix-10 ABS on '93 minivan

I picked up a '93 Plymouth Grand Voyager only to learn I was
subjecting myself to a mess with a Bendix-10 system that's acting up.
I've been doing a little reading on it here and elsewhere over the
past couple of days.

The system is apparently leaking down somewhere because I can hear the
pump motor cycle for a few seconds everytime I press on the brake
pedal and occasionally on its own while I'm driving. The brake light
is on and the ABS light is apparently burned out or removed. You can
see tape residue where they used to have tape over the ABS light.

First off, is there any way for me to determine if the leak is coming
from the accumulator or the piston? Is there anywhere else the ABS
system could be losing pressure? I know the pump and piston are
covered under the lifetime recall warranty, but I'm willing to bet any
dealer would want to blame the accumulator first since they can make
some money on that part. Also, as I understand it, a dealer will
charge the diagnostic fee for checking this out but they have to
refund it if the only problem is related to the recall. This is a
concern because the 2 dealers I called so far was $85-110 just to hook
up their scan tool for codes.

Also, I notice that the accumulator is virtually the same as the one
on my '90 Olds. I'm retiring that car and the accumulator was replaced
it in a few years ago. I'm tempted to try swapping it onto the minivan
to see if that helps.

I appreciate any advice anyone can offer. If worse comes to worse I'm
considering following some info I found elsewhere and converting it to
non-ABS. My main goal at the moment is to see if there's a way to
locate the source of the pressure leak on my own, or at least to
eliminate any specific sources.

Dave

 

There were many posts regarding ABS systems on this site back in the
early to mid-1990's

There were one or more recalls on these early ABS systems.

Hopefully, the previous owner(s) had them done. I would suggest
entering the last 8 digits of your VIN into the "owners" section on
Chryser's website, so see if there are any remaining recalls.

Glenn, it seems like you addressed this topic just a few weeks ago,
and said that the accumulator was not covered under the recall.

-KM

 

Yes, I spent a fair bit of time reading those older posts.

This is why I want to see if I can determine whether it's the
accumulator leaking, the piston, or somewhere else. I do understand
that the accumulator is not covered. I can't help but feel that
Chrysler felt like they dodged a bullet by not having that included in
the recall, since apparently they were fairly prone to failure as
well. If nothing else, it gave them a scapegoat they could charge for
when minvans came in for recall warranty repairs. From what I
understand and have read, even if the recall work was done previously
there's no guarantee the same problem won't develop again. Some people
who made posts in the archives made repairs done multiple times.

Dave

 

The accumulator is not covered

Glenn

 

I understand that, I tried to communicate that in both my previous
posts. That is why I want to know if there's a way for me to determine
whether it's the accumulator or something else such as the piston
(which is covered).

 

What you are describing right now is a faulty accumulator. When the pump
charges up the accumulator, it stores pressure of 2100 psi which should give
you at least 3 to 4 pumps of the brake pedal before the pressure drops to
1600 psi and acitvates the pump to recharge. If the accumulator is bad one
pump of the pedal will drop the below 1600 psi , turnign on the pump and
possibly the red ABS lite.. If it were the pump that were bad (and it could
go out next because the accumulator is going to wear the pump out) the red
lite would never go out because the pressure would not reach the specified
pressure to turn it out.
Just from what you are telling me here . yes....im going to blame the
accumulator due to the symptoms you describe
Take it to an after market shop and have them try to diagnois it and see
what they sell you. Then when they cant fix it watch how fast they blow you
off to the dealer. And there is more to it then just hooking up a scan tool
and getting fault codes. a special pressure gauge has to be connected to
read the pressures of the pump and piston side of the Hydraulic assembly
which includes depressurizing the system and remove the pressure side hose.

good luck with that

Dave, not a good vehicle to put alot of parts on for the brake system..Parts
for this system are getting hard to find and Chrysler has made it almost
impossible to get parts for this system and the ones they do have will cost
you some ridiculous price. I beleive they want these cars going to the
salvage yard so the recall will not bite them anymore. that accumulator i
think is over $300, the dual function pressure switch that controls the
pump was $53 and now I think is $175.

 

Thank you! I've decided that I'll try going to a pick & pull yard
tomorrow and take a shot (yes, I understand it's a crap shoot on these
things) at getting a good accumulator.

I don't plan on sinking a bunch of money into this van and if I
determine that it's a money pit it I'll get rid of it. Thank goodness
I don't have much in it to begin with. My next contract job won't
start for a few weeks while I wait for a security clearance check, so
I have some time I can invest. I might as well use some of it to see
whether I can get this thing road-worthy. Perhaps I should also look
for another dual function pressure switch while I'm at the yard, since
it appears that's not covered under the warranty either. The only
manual I have is Haynes and it doesn't show that switch. Can you give
me some hints on locating it?

Dave

 

Glenn, what year did Chrysler move off of this Bendix system, and what
are they using now?

Just curious.

KM

 

Well now, that does make things more interesting doesnt' it, LOL. From
the symptoms I've described, does it sound like this could be a
culprit in my situation? Regardless, I'm sure I won't have the
required socket in time for this particular trip to the junkyard. I
suppose if it looks like I'm going to need it I could yank the whole
master cylinder because it sounds like I'd get the switch along with
everything else.

For tomorrow I'll just go in and pull an accumulator. It should be a
quick trip.

I appreciate the help max.

Dave

 

I know from what I was reading last night that '93 was the last year
for the Bendix-10 system in the minivans.

If they didn't use the pump motor to pressurize the brakes, I'd look
for a way around the ABS. As it is, if I don't fix this then the motor
is bound to wear out prematurely. I may still use the guidelines I
found on another forum to convert to non-ABS, or I may just decide to
sell the whole thing.

Dave

 

The dual function pressure switch is located on the very bottom of the
hydraulic assembly. it has to be removed while the vehicle is in the air
with a special socket, It has 3 wires going to it

 

I found this on Allpar.
http://www.allpar.com/forums/index.php?showtopic=88112&hl=bendix-10

Dave

 

as I said, don't put alot of money in it, im sure the salvage yards aren't
giving them away. if the unit is already off you can get the switch off

Glenn

 

Just curious, what are the guidelines you see

 

Anytime you use a system that constantly maintains a pressure of 2000 psi
at ALL time you are asking for problems (such as the Bendix 10 ) Bendix 4
for something like pressure on demand.

Glenn

 

If you are handy the smartest thing you can do is pull out all that ABS
crap and make it a standard brake system. You should be able to get
the parts from a wrecker. The Bendix-10 system is horrible I never
heard one good word from any Chrysler mechanic about it - and when
I was shopping for a used van several years ago my brother in law who
is a certified mechanic for a Dodge dealer warned me not to touch one of
those. And I myself am handy with tools.

ABS only works in limited circumstances anyway. If your barreling
down a road covered with ice or gravel ABS won't do squat. I've
tested it under controlled conditions with my 95 van which has the
ABS bendix 4 system. About the only thing it will do for you is help
in rainy weather - and if you are speeding in the rain you probably
deserve to smash up anyway.

Ted

 

Dave could you post these I do not have an allpar account and since it
appears
to be some sort of bulletin board forum those instructions probably will not
last
very long. If you post it here it will go into the google archives.

Ted

 

No problem. Special thanks go to Fabinator on Allpar. He posted these
in a couple of the Allpar forums, this one was from 1/30/07.

I have a '91 Imperial with the Bendix 10 ABS system, this brake setup
came in many cars and vans from the early to mid '90s. The interesting
but somewhat short-sighted idea of electric-assist brakes instead of
vacuum-assist brakes are the main problem. The hydraulic pump tends to
die, and teh accumulator which stores pressure tends to leak... not to
mention frequent and costly computer related failures.

A class-action lawsuit against Chrysler mandated free replacement of
the pump motor and accumulator for the life of the vehicle, but the
brakes still suck. I have sucessfully converted my Imperial to vacuum-
boosted brakes, without the ABS feature (good ridance). Here's how I
did it, and how much it cost.

You will need:

One vacuum booster from an '88-'93 Dynasty or New Yorker

One master cylinder from same vehicle (you could use any MC that fits
onto the booster, just get the brake line fittings with it

One proportioning valve to match the vehicle (for the Imperial, use
one from a 4-wheel disc car. Vans will need one from a similar van).
The proportioning valve is NOT optional, the Bendix 10 system is not
equipped with an external unit.

The brake pedal from the same car you got the booster from (ABS uses a
different size pushrod from the pedal arm to the booster/control unit)

All the fittings from the prop valve to the brake lines, and the two
small lines from the prop valve to the MC.

Check your intake manifold to see if it has a free 3/8" fitting with a
cap on it. If it doesn't you'll need one from the junkyard.

One quart of brake fluid (I flushed the entire system with less than a
quart)

A double-flare tool, taht can flare 3/16" tubing

Small tubing cutter

10" crescent wrench, 11mm wrench, 13mm wrench, 15mm wrench, 17mm
wrench, 18mm wrench, heavy duty cutters (for cutting brake lines),
socket wrench, 3" extention, 13mm deep socket, 15mm standard socket,
3/8" standard socket... this is what is needed if you use the MC from
an '88-93 Dynasty or New Yorker, using a bigger MC off of a D-150
truck may require other tools. Due to the fact I may have forgotten
something, and you (or me) may have an odd car, bring a good variety
of tools.

Phase 1: gathering the parts

the first thing to do is get the pedal off of the donor vehicle, it's
much easier to remove the booster once the pedal is out of the way. To
do this, remove the under-dash panel (the black plastic one, not the
one that matches the interior), use the crescent wrench to grab the
end of the pivot rod for the pedal arm (it's the one on the driver's
side, then use the 15mm socket and ratchet to remove the nut on the
pivot rod. After the nut is removed, the rod will slide out toward the
driver's side. remove the clip holding the booster pushrod to the
pedal arm, and the pedal should be free.

Step 2: Remove the master cylinder. Undo the two brake lines from the
driver's side of the car with the 11mm wrench, then unbolt the MC from
the booster using the 13mm socket, or 13mm wrench. It should now be
free.

Step 3: remove the booster. You will need to remove all vacuum lines
from the booster, but you may want to save the booster-to-manifold
line. I used new 3/8" oil cooler line. If you need the vacuum fitting
for the intake manifold, grab it. Once the MC and brake pedal are
removed, it's held to the car with four 13mm nuts from inside. Remeve
them starting with the one at the upper passenger-side corner, it's
the hardest one, get it with the 13mm wrench. All the other nust are
easily accessible, the lower passenger-side nut is easiest to get with
the wrench. The lower driver's-side nut is easiest with the 13mm
socket and 3" extension, the upper driver's-side nut is easiest with
the 13mm socket w/o extension. The booster should now be free, pull it
out from the front.

Step 4: remove the proportioning valve. Before you dig in, note where
the brake lines go... the driver
s side front goes to the front front fitting, front passenger side
gors to the rear fitting, and the rear lines go to the bottom... not
sure which way, but also not sure if it matters too much (I matched
the orientation to my Dynasty). Unbolt the prop valve from the
bracket, and cut the lines to the calipers a couple inches from the
prop valve. Leave the lines to the MC intact. Remove the prop valve
bracket.

You're done here, go back home.

Phase 2: Gutting your vehicle

Everything comes out. Remove the brake pedal, master control module
(Bendix 10 equivalent to master cylinder), and the pump assembly. The
MCM is attatched to the firewall in the same way, but it has four
lines coming off of it, instead of two... this is why you needed the
prop valve. The lines are in different areas, some hard to reach. You
will also need to disconnect a whole lot of electrical connectors.
Once you have it out, do what you want with it. You may need to save
the caps... the MC I got had none.

the pump motor is attatched to the car at three points: two bolts into
the top of the diff cover, one bigger bolt goes to the bell housing.
Remove the heat shield with the 3/8" socket first.

Phase 3: fitting and installing parts

The first thing do do would be to trim the brake lines, install the
proper fittings, and re-flare the ends. Once you have this done,
install the prop valve bracket. Attatch the lines to the prop valve,
and bolt the prop valve to the bracket. That part is done.

The booster is different from the ABS MCM, so you'll need to cut the
rubber thing in the firewall out of the way. Install the booster, and
hool up the vacuum line. My car had the heater control line on the
manifold, leave it there. If your car needs the extra fitting install
it now.

Install the non-ABS brake pedal, and transfer the pad if you want. My
Imperial had stainless trim on the pedal pads, and the donor car did
not... that's why I transferred the pad.

Install the MC and begin to thread the brake line fittings... you need
to bleed the MC a little before you tighten them all the way. Fill the
MC, and slowly pump the pedal once. If you can see brake fluid
dripping from the fittings, tighten them up... if not, either the
fittings were too tight, or you need to pump the pedal again.

Bleed the lines. Start with the left-rear wheel, go to the right-rear,
then the left-front, and finally the right-front. Keep the MC res
topped off, you don't want to start pushing air int the lines.

I think you're done, leave some nice tire marks.

This took me four hours at my house, and 1.5 hours at the junkyard.
The booster cost $15, the MC cost $5, the prop valve cost $10, the
pedal cost $6, and the brake fluid cost $7. the brake lines were so
short, they didn't charge for them.

An easy day's work, and less than fifty bucks may just save your life
later. Sounds like a good deal to me. I don't know how to post this in
a "more permanent" reference or archive section. If a mod could put
this post somewhere more useful, please do... also feel free to modify
anything, or add to it. If anybody wants more detailed information,
let me know what, and I'll post it. I'll be posting pictures on my
cardomain site soon, I'll post here when they're up.

 

Hah hah! That's stickin' it to the man! I love solutions like that.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')