Leak near top of Front Driver AHC Shock

[Qtonic]

I noticed a leak that appears might be originating near the top of the front driver side AHC shock. It seems to proceed down to the location in the second photo.

I've done an AHC pressure test and get 8.1 in the front. I will pick up a 30mm socket and adjust my torsion bars tomorrow in case excessive pressure is causing the leak.

I'm looking for other opinions. Does it seem like I'm on the right track? OR is there another obvious culprit I should be looking at?

Thanks,
Q

 

[PADDO]

I noticed a leak that appears might be originating near the top of the front driver side AHC shock. It seems to proceed down to the location in the second photo.

I've done an AHC pressure test and get 8.1 in the front. I will pick up a 30mm socket and adjust my torsion bars tomorrow in case excessive pressure is causing the leak.

I'm looking for other opinions. Does it seem like I'm on the right track? OR is there another obvious culprit I should be looking at?

Thanks,
Q

Inspect the flexible line union to shock actuator shaft - the cup at the top of the shock actuator secured with two bolts - because that’s where your leak seems to be. There’s an O ring and backup ring that internally seals the union and that could have failed or the swaged flex line to union cup could be on its way out.

By all means get that pressure down to where it needs to be however the weeping that you often get due to high neutral pressure is usually past the actuator shaft seals and you see the results on the lower shock body.

 

[planomateo]

Looks like you have some grease around your inner CV boot as well. Might want to inspect your boots.

@PADDO - can you buy O-rings individually?

 

[PADDO]

@PADDO - can you buy O-rings individually?

Yep

 

[Qtonic]

Inspect the flexible line union to shock actuator shaft - the cup at the top of the shock actuator secured with two bolts - because that’s where your leak seems to be. There’s an O ring and backup ring that internally seals the union and that could have failed or the swaged flex line to union cup could be on its way out.

I appreciate your advice. I'll look up some diagrams and find what you're referring to. Generally, though, where would I inspect from? Underneath or from the top?

Thanks again.

 

[PADDO]

Have a look through the wheel well, so horizontally, at the top of the shock actuator tower. I suspect you might find the hydraulic line flex to rigid connection is corroded and leaking. Also might help to give it all a good spray with degreaser if the leaks origin isn’t obvious.

 

[Qtonic]

Mind giving this a look for me? I'm not exactly sure what the different components are and what to look for.

 

[Qtonic]

Looks like you have some grease around your inner CV boot as well. Might want to inspect your boots.

Will do. Thanks for spotting that.

 

[Qtonic]

@PADDO I cranked the torsion bars and got my pressures in a good range, but the leak seems to have persisted. Someone else was driving it for a while and a couple days after getting back in town I took it for a ride and heard the pump gurgle and the 'off' light flashed. Sure enough, the reservoir was dry.

So I'm going to replace the o-ring and backup ring. Can you verify my plan?

1) Set truck to low. I hope this burps out the air that entered when the reservoir ran dry.
2) Open damper and bleed front
3) Remove and replace rings. There should not be pressure anymore right?
4) Add sufficient fluid and start truck

The remaining fluid in the system is fresh, so I'm not planning to do anything with the back unless I'm misunderstanding something.

Sound about right? Thanks for your help.

 

[PADDO]

Sounds like a reasonable plan, did you give the area a very good clean with degreaser or brake clean? Sounds like the leak is large enough that you should be able to see it’s origin pretty easily when the system is pressurized and operated - either it’s coming from a failed o ring or the flex to rigid swagged fitting in the pressure line is leaking. You’ll need to bleed after opening the system for your repair.

 

[Qtonic]

Sounds like a reasonable plan, did you give the area a very good clean with degreaser or brake clean? Sounds like the leak is large enough that you should be able to see it’s origin pretty easily when the system is pressurized and operated - either it’s coming from a failed o ring or the flex to rigid swagged fitting in the pressure line is leaking. You’ll need to bleed after opening the system for your repair.

While attempting to pin down the exact location, I noticed something that I'd missed before. The cushion has failed. I was able to pull a broken piece out. Makes me wonder if the shock was damaged. I'll pull it off and investigate. Thanks again for your help.

Edit: Everything about the line connecting to the top appears dry. I'll do the o-rings when I'm in there, of course.

 

[krispykritter]

Curious if you ever solved this? I need to start tackling it once I get back home from this trip I'm on.

Noticed some wet areas after doing brakes and bearings and assumed it was just dirty hands. During this trip, it seemed like the truck was adjusting the front pressure way more often than I was used to. Sure enough, it seems to be leaking from the pressure lien to strut connection, but I haven't cleaned it all off to see how bad it is or if that is source yet. Really hoping it's just orings as that pressure hose seems to be north of 300$

 

[Qtonic]

Curious if you ever solved this? I need to start tackling it once I get back home from this trip I'm on.

Funny you should ask. I just did it today.

Yes, you will want to hope it's just o-rings. You might check your pressures and adjust torsion bars if necessary. I've heard that weeping that occurs from the lower shock body can be stopped by getting pressures in check, though I doubt a leak from the top would resolve by getting them in line. Still, it's probably a good idea if you've never checked it. Other than that, look at the hydraulic line for signs of fluid. In my case it was easy to see it was dry. If so, you're in for o-ring and backup ring and hopefully that fixes it.

Good luck!

 

[Qtonic]

Resolved

In my update in post 11 I had found that one of the cushions was disintegrating badly. So I knew I had to replace those. In my case I could not get the top nut off, so I had to cut through the shock with a sawzall.

What I found was crazy. The silver shock tube was badly eroded where the cushion had failed, so much so that it could have possibly been leaking from pin holes in the wall of the tube. The retaining brackets in that area were also toast, although thankfully intact enough to prevent wear to the shock mount on the body. I ended up replacing all parts on both sides. PS was fine, but again I couldn't get the nut off, so if I wanted to refresh the o-rings and cushions, I had to replace the shock too.

I think the retainer above the disintegrated cushion had not been seated correctly at the factory. It's slightly fiddly to install and keep in place when tightening everything, and the wear pattern looked like it was off. My guess is the movement caused the cushion to wear and fail, leading to more movement that disturbed the hydraulic-to-shock connection and o-rings or, like I said, the side wall of the silver shock tube itself could have been so compromised that it had small hole.

Another possibility is that a leak occurred first from the o-ring and the cushion failed after being consistently wet with fluid and the resulting movement exacerbated the problem over time.

Anyway, it's fixed now!

Top-tip: Anyone who ever needs to get to the top bolt should use a pass-through ratchet.

 

[krispykritter]

I did check pressures recently and got them back to where they should be for the front. Rear is still out of spec, due to saggy springs I assume. The fluid is definitely coming from the top, rather than the shock body. Haven't had time to actually nail it down. It's a very slow leak.. .it probably squeezes a bit out on really big bumps.

As for the o-rings...where would I source them? Are they just standard rings I can just get in a generic kit, or do I need to have the Toyota specific parts? Been having trouble finding them in a parts diagram as a stand-alone part.

Planning to start collecting parts for the ahc lift and will tackle all the other maintenance bits while I'm in there.. Lower ball joints, ahc spacers, new rear king springs, crank up the stock torsion bars, weeping shocks, etc etc. Going to be a fun weekend once I've got everything I need.

 

[Qtonic]

As for the o-rings...where would I source them? Are they just standard rings I can just get in a generic kit, or do I need to have the Toyota specific parts? Been having trouble finding them in a parts diagram as a stand-alone part.

Planning to start collecting parts for the ahc lift and will tackle all the other maintenance bits while I'm in there.. Lower ball joints, ahc spacers, new rear king springs, crank up the stock torsion bars, weeping shocks, etc etc. Going to be a fun weekend once I've got everything I need.

Up to 03/99:
O-Ring - 96711-19009
Backup - 90562-09005

From 03/99:
O-Ring - 90301-11022
Backup - 90562-12003

You might consider getting an extra backup ring. It's a split ring made of a fiber material and has to be wound in on itself a little to get it in place, then spread out inside the cavity. It was a little awkward and I had to be careful not to tear it or deform it too much. For an extra couple dollars I would have liked to have a second chance if necessary.

 

[krispykritter]

Awesome, that's excellent! Thanks for the heads up, I'll definitely grab a few. Pretty guaranteed to screw up the first one!

 

[JGG]

What I found was crazy. The silver shock tube was badly eroded where the cushion had failed, so much so that it could have possibly been leaking from pin holes in the wall of the tube.
[...]
like I said, the side wall of the silver shock tube itself could have been so compromised that it had small hole.

Like this?
250k and NY vs 110k and California

In my case I could not get the top nut off, so I had to cut through the shock with a sawzall.
[...]
Top-tip: Anyone who ever needs to get to the top bolt should use a pass-through ratchet.

For the other mudders:
I think the one below is the best and cheapest option to buy. I paid €15 for a number 22 and shove a 32mm steel pipe OVER it. After that it came lose. (while doing it that way, keep you're eyes on you're fender!)

 

[Qtonic]

I highly recommend that wrench style if not using a pass-though socket (like this).

The flex-head ratcheting wrenches, which I already owned, did not give me the depth access that I needed to get down to the somewhat-recessed top nut. So good call recommending that. I will note that I have found more uses for the max axess set since I bought it, so it still gets a 'recommend' from me.

It's also likelier easier to fit a cheater bar on (because the handle is straight) compared to the offset style wrench. It might also make a difference in accessibility in low clearance situations, like in the rear. The pass-trough socket also ratchets, which is very helpful.

 

[Salty Sailor]

Hi would you mind having a look at my thread and commenting please. Thanks so much in advance.