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Patrick MegaDork
2/17/18 10:00 p.m.

So who owes me $1.50, because both of my long distance diagnoses via text were right laugh

glad it wasn’t full on rebuild time, those guys sound reasonable.

Pete Gossett
Pete Gossett MegaDork
2/18/18 4:49 a.m.

In reply to Patrick :

Damn right I owe you, that's why I messaged you first!

Pete Gossett
Pete Gossett MegaDork
2/19/18 1:46 p.m.

I finally had time to take a look at the ABS setup on the truck. 


From what I can tell this is the Kelsey-Hayes 3-channel system, and it's showing the following codes:

  • 61 - right front reset switch open circuit

  • 66 - pump motor relay short

  • 86 - ABS indicator lamp shorted

The last one is odd, as the ABS lamp works fine. The second one is most concerning though, since I've not been able to find a replacement module or rebuilder. 

Im not concerned about retaining the ABS, so I could swap the MC and re-plumb around the EHCU, but that will defeat my TC lockup clutch circuitry. 

I think for now I'll leave the ABS alone, wire a toggle switch directly to the trans harness for the clutch, and continue to live without cruise control. 

Pete Gossett
Pete Gossett MegaDork
3/3/18 7:36 p.m.

Spent a little time on the truck, but no pics(yet). I swapped out the blower motor, it's nice not having the fingernails-on-a-chalkboard anymore. 

Next I started wiring up a circuit to manually lock up the TC clutch  since my failed(and apparently NLA) ABS module is preventing any voltage from getting to the TC lockup circuit, I wired a fuse from the battery to a switch in the dash, then routed the wire under the truck. I need to crawl underneath tomorrow, T off it to the 2nd wire on the trans, then manually ground the circuit since it also has a switched ground. Schematic for reference, though I don't have 12v from the brake pedal switch due to the ABS problems.

I also swapped out the rear brake shoes. I was surprised to find I have the larger size drums, I'm not sure if that's part of the 3-channel ABS system, or just an upgrade option, but I'm happy to have them! Unfortunately it's a real pita to change them by yourself as there are multiple springs and pieces that need held together as you install them. Fortunately a friend stopped by & was able to help. Now let's hope the self-adjusters work, as there's no plug on the backing plates for adjuster access...

dj06482 SuperDork
3/3/18 9:28 p.m.

Grease the adjusters on the rear drums, find a steep hill, back down at 25 MPH and then hit the brakes hard, right on the edge of lockup until you come to a stop.  Repeat 3 times and your rear brakes will be as good as they're going to get.

Pete Gossett
Pete Gossett MegaDork
3/4/18 10:53 a.m.

I walked out this morning to find a puddle under the LR wheel, pulled it apart & it looks like it was leaking from the front of the wheel cylinder. Pushed the plunger in w/a screwdriver, cleaned it up and adjusted both sides, then put the drums back on & checked the brakes. They seemed to be holding pressure & after some adjustment on both sides I had decent pedal feel. 

I finished wiring up the TC clutch manual lockup switch, then took it for a drive. At the stop sign down the street the brake pedal dropped again. Crap. I need to check if the leak returned. I tried the lockup clutch while I was out, but it didn't seem to work either. Damn do I hate working on vehicles...

Pete Gossett
Pete Gossett MegaDork
3/4/18 11:54 a.m.

Well I checked the brake fluid & it's still full. I'm guessing I either have air in the lines, or need to readjust the drums. 

At this point if I end up needing to re-bleed the brakes, I'm just going to bypass the NLA ABS module so I know there's no chance of air remaining in the system. 

Pete Gossett
Pete Gossett MegaDork
3/25/18 6:29 p.m.

I finally made a bit of progress on the truck today. First of all - how have I lived my whole life without one of these?


The GM adaptor is a bit jankey, but seemed to work well after I finally got it sealed. 


And finally the brakes actually work well again!

Next I replaced the headlight switch because the cluster lights were intermittently inop, and I was pretty sure I lost the taillights too when that happened. 

Then I got setup to tow. 


I installed the P2 in the ashtray, since there’s no good place under the dash for it & I won’t be using the ash tray anyway. 


I still don’t have any torque converter lockup & im not sure why. I’m tempted to take it back up to the mechanic in IL and let him figure out a redneck fix to work around the dead/NLA ABS module. 

Pete Gossett
Pete Gossett MegaDork
5/28/18 7:59 p.m.

No major updates on the truck, but I did tow a 6’x12’ U-Haul trailer 840mi up to IL last Friday, cram it 100% full of crap floor-to-ceiling, wall-to-wall, and front-to-back, then tow it 840mi back home on Tuesday. 

The good news is the truck made it there & back with out breaking down. On the way up it was cool & rainy so I was able to keep steady between 70-75 empty, but it was hotter on the way home & the temp gauge started climbing if I went above 70...or turned on the a/c, sadly. That was somewhat ok though, as having the windows down helped drown out the drone of the ever-growing hole in the muffler & evacuated the exhaust fumes. 

I averaged 9.6mpg loaded, which is better than I expected. However the day after I got home the driver side seatbelt decided to no longer latch.

At this point I definitely need a muffler & shocks. Then I need to replace the windshield so it’ll stop leaking into the dash. I have a pair of seatbelts on order too. 

I’ve never been able to get the TC to lockup either, so I’m starting to think the lockup clutch may be bad. I need to find a local trans shop & see if they can figure it out and/or rig it up to work somehow without the ECU’s involvement. I might just have them go through the trans too & see if there’s anything that could be done to help make it more durable for towing. 

ClemSparks UltimaDork
5/28/18 8:33 p.m.

It really doesn't seem like it should be heating up like that.  What do you suppose that is about?  I suppose a non-locking torque converter could put out some extra heat, but I would think if your cooling system was in good shape, it should be able to handle that.  Maybe you've already mentioned a potential cause and I'm just not remembering.]

At any rate...glad it's working as a tow vehicle for you!  Steady improvements are fun!

Pete Gossett
Pete Gossett MegaDork
5/28/18 9:05 p.m.

In reply to ClemSparks :

My understanding is not having lockup really generates heat, based on what I’ve been told. 

Pete Gossett
Pete Gossett MegaDork
8/28/18 9:07 p.m.

I haven’t been driving the Suburban much this summer, but I took it to Aeromoto’s shop a couple weekends ago so he could lend a pair of hands to help me wrestle a new slave cylinder on the RR brakes. 

I went out to start it tonight for the first time since then. It started up fine like always, but died a couple seconds later. I tried again, but it took several seconds of cranking before it fired, and it was running quite rough. It smoothed out a bit after revving it, but I needed to get to the store & didn’t want to risk getting stranded, so I E36 M3 it off & took the Miata instead. 

So it looks like I have a project for this weekend... 

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