ABS on 89 Wagoneer LTD Info wanted

I send this out to all who read this who also have the ABS system that has the pump that groans every other time you hit the brake.
I am looking for your experiences in the ABS when compared to other vehicle's brake systems
My 89 Wagoneer's ABS has always been spongy with major pedal travel. 90% of the braking occurs in the last few inches of travel. This has always happened...I want to know if there are others out there that have this same experience. My 96 JGC Limited with ABS doesn't seem to have the same ABS system (no groaning pump) and it seems to have a firm brake. And my 90 Cherokee sport with regular brakes has awesome grabbing!
The reason for my query is that I had the ABS recall performed a few weeks ago and the braked are spongy as they ever were. Even to the point where I believe it's worse than it was previously (it may be that driving the 90 Sport for the last few weeks I forgot how spongy the LTD was). I need to know if I need to have further brake work done...
any ideas?
Ed
web/gadget guru

I had the cursed Bendix 9 ABS system just as you have in my 90 Renix. I swapped it out for the vacuum setup from a 91. From what I understand the accumulator resevoir has a valve or seal in it which leaks causing the pressure to bleed off effectively making the booster pump run until the pressure switch is closed. In my case my ABS pump ran 100% duty cycle for about 6 mos. until it finally said "no more, I quit". I also ripped out that giant ABS cpu from underneath the backseat for more storage room.

Ed Kummel said:

. . . I need to know if I need to have further brake work done...
any ideas?
Ed
web/gadget guru

Click to expand...

The early ABS systems are expensive to repair, and remain flaky (for most of us) even after repairs. Search around on the forums - there is quite a few write ups. The best/ easiest solution is to replace it with a 95/96 conventional brake booster. . .

Check your brake linings and self adjusters, as they wear the hydraulics have to make up for the extra piston travel.

We have the same system on our LTD, the first problem we had was worn out shoes, and one self-adjust cable broken. The parking brake wouldn't work after adjustment, excessive pedal travel, I pulled the drums and started calling auto parts.

The second problem was corroded terminals on the pump relay, totally different problem/symptom.

I have noticed the pedal is "soft". I have pulled some pretty impressive awwshit stops without problem. What I have not done is lock up on dry pavement; i kinda like that. :~)

It's a POS. Find a booster/MC/pedal/prop valve from a 95/96 and swap it out. Prepare to flare and bend a couple lines. I did the swap for less than $100, solved all my braking problems and freed up 2 relay sockets for my headlights.

Is the pedal spongy also when you have pumped the booster pressure away? Mine feels kinda spongy when there is boost pressure available. Excessive travel comes from those rear brake shoes being far away from the drum. The hydraulic modulator is PITA to bleed but with a friend and lot of brake fluid it can be done.

When I bled my brakes I noticed that when I was pumping the boost pressure down there was air in returning fluid in the reservoir. After those bubbles were gone power on and wait that boost pressure to rise again. I repeated this about 5 times and there is no more(at least not that much) air coming out from the boost circuit. And after this it is again good time check modulator for air. There can be lots of dirt trapped in modulator and to get it moving you need to control those solenoids to open. For this you the tester or do it manually like I did. It is good idea to buy original brake service manual from eBay.

After doing all this you know why these brakes are expensive to repair.

-Kimmo-

Slo-Sho said:

I had the cursed Bendix 9 ABS system just as you have in my 90 Renix. I swapped it out for the vacuum setup from a 91. From what I understand the accumulator resevoir has a valve or seal in it which leaks causing the pressure to bleed off effectively making the booster pump run until the pressure switch is closed. In my case my ABS pump ran 100% duty cycle for about 6 mos. until it finally said "no more, I quit". I also ripped out that giant ABS cpu from underneath the backseat for more storage room.

Click to expand...

Ok


So, let's say that I am going to go the route of replacing the cursed ABS system...
I can get away with the master brake cylinder, vacuum booster and the necessary vacuum lines down to the combination valve, right?
Then I can remove the fuse to the ABS system and I should be good to go?
Are there any "gotchas" I need to worry about? something like the actuator from the brake pedal being the wrong length, or the bolt holes in the firewall not the right distance for the vacuum booster mounting?
I'm just taking stabs at possible issues...Anything I'm missing here? It seems a little too easy of a swap!
Ed

Ed Kummel said:

Ok


So, let's say that I am going to go the route of replacing the cursed ABS system...
I can get away with the master brake cylinder, vacuum booster and the necessary vacuum lines down to the combination valve, right?
Then I can remove the fuse to the ABS system and I should be good to go?
Are there any "gotchas" I need to worry about? something like the actuator from the brake pedal being the wrong length, or the bolt holes in the firewall not the right distance for the vacuum booster mounting?
I'm just taking stabs at possible issues...Anything I'm missing here? It seems a little too easy of a swap!
Ed

Click to expand...

Get the master brake cylinder, vacuum booster, portioning (combination)valve, the single large vacuum line going from the booster to the intake manifold AND the fitting out of the manifold (yours will have a plug). Get the brake pedal from the donor vehicle - I got the whole brake pedal assembly from the donor but found I only needed to remove the pivot bolt and replace the pedal in my Jeep. My experience was that the pin the actuator bolts to was about 1/2" too low (or high? it's been awhile)

The discussion about spacers and correct distance for the actuator: Looking at the back of the donor booster, there is a foam pad. . . UNDER the foam pad is a spacer. It's all glued together - just leave it alone. Maybe if you got a new one it wouldn't come with it? or people have pried it off? Don't know - length wasn't an issue for me - Especially with replacing the brake pedal.

You'll either need to reflare the lines or get adapters as the fittings are different (SAE vs Metric?) and not a direct bolt on to the portioning valve. When I took it off the donor vehicle, we left fittings in place, and cut the brake lines. I was able to reuse the old fittings on my lines.

You should (and a lot of people don't) replace the rear cylinders as Non-ABS systems have a slightly larger cylinder. I did a full brake job as when I was bleeding out the system, one of the bleeders on a front caliper broke.

The ABS plumbing across the back of the engine will be in the way so it'll have to be cut out to make room for the new booster, and I removed a handfull of fuses.

My experience was replacing a 91 ABS (same early Bendix system) with a 95/96 booster assembly (best direct bolt in replacement). I had an experienced friend come over and do the flaring. The only thing I miss is that I don't get the Red light on the dash indicating the parking brake is on.