aptoslexus

First time working on this car ( 98 LS 400), I decided to change out the plugs. The trouble was removing the air cleaner assembly. It was stubborn and there really isn't any tutorial that I could find that addressed this in any detail. I was working on removing one of the vacuum? hoses attached to it and the plastic part broke off flush at the air cleaner assembly leaving the rest of it in the rubber hose. I'm not even sure what this hose does, but it looks like a PCV hose or something. It goes down and into the engine between the ignition coils on the first and second cylinders and attaches toward the front of the air intake pipe. Seems to be a common issue as a technician had had a similar problem on a hose at the rear of the assembly and had slathered sealer over it to repair it.

Has anyone ever repaired something like this? Replacement air pipe part is $255 and I'd rather not throw that kind of money at a frail plastic part.

Doc Yota

Exact same thing happened to me on my 99 when I replaced my coolant temp. sensor. I have taped a very small rubber hose and snugged it into the hose with the broken plastic and that black box device until I can locate an aftermarket intake or figure something out...this is just temporary

sha4000

iTrader: (1)

Use epoxy glue to re-attach it.

aptoslexus

The hose in question is under his sleeve in this pic:
https://www.flickr.com/photos/landar...7622883357340/
Anyone ID what this hose does? Car seems to run fine with it broken.

Yeah, it's not the greatest design, what with people having to wrangle this box out of the way all the time. Bound to be a problem. I might see if I can pick up a fitting at the hardware store and screw it into the plastic.

sha4000

iTrader: (1)

Your pic is not showing up for me. All the hose and plastic pieces are brittle under there so you really have to take your time when removing them.

Largefarva

I can see it, goes to a steel line that runs across the intake, looks about 10mm. I'd just remove the end and super gulue it back on.

aptoslexus

That is illusory. It actually bends 90 degrees straight down and in between the ignition coils just below. It's not the one he's working on but the one in front under his sleeve. I thought of gluing it, but I've never had much luck with glue. Always seems to just immediately break again.

oldskewel

iTrader: (1)

This might be similar enough to help your problem ....
on my '91, the vacuum hose from the air intake to the PS idle-up air valve snapped off at the air intake. Brittle from age + heat.

My solution worked perfectly: I got a ~1.5 inch section of hard brake line (bought the 3' length at pep boys for ~$5 and cut what I needed). Diameter of the brake line sized to match the inner diameter of the vacuum hose (that was brittle as well, and I replaced as well).

Drilled a hole in the air box so the piece of hard line would press fit in there.

Then the vacuum hose attached onto the brake line.

I may have put some glue to be sure the hard brake line piece does not pull out of the air intake. Working just fine for several years now.

RA40

iTrader: (6)

This thread and PD's advice, or you can do like I did.

https://www.clublexus.com/forums/ls4...e-fitting.html

aptoslexus

Thanks for the link. Good info there.

Doc Yota

Pretty good solutions here. Thanks for the info fellas. I'm going to get to work on this now. What does that black box do anyway? Does anyone know?

aptoslexus

Here's how the story ended. I had to cut the plastic piece out of the hose, as I couldn't brute force it out with a metal hook or pliers. They were married for life. No wonder it broke off. Then, just to try, I bought some Loctite plastic glue and tried to glue the plastic bit back onto the air box. Bubble gum would have worked better. Didn't stick at all. $6.50 for glue that I wouldn't pay a dime for ever again. Then I bought a 1/4 x 3/8 brass fitting:

I drilled out the hole gradually until I could start screwing the fitting into the air box. It screwed in nicely with no tapping using a wrench:


It's tight with no glue used. I finished it off with some silicone sealant and a new hose.

PureDrifter

iTrader: (10)

proper fix for that issue, good job

YLK

I have the same problem. Was about to start the repair after
buying the brass male barb hose fitting until
I found the following plastic knowledge base article...

Can you thread plastic and metal NPT fittings together?
www.usplastic.com/knowledgebase/article.aspx?contentkey=803
=================================================================================
To be able to thread plastic and metal fittings together the male fitting has to be plastic and the female fitting has to be metal.
When fittings with a tapered thread such as NPT are tightened the male fitting is compressed and the female fitting is stretched
(tensile stress). In general most materials have a higher compressive strength then a tensile strength. This is why the female
fitting is the one that will crack when over tightened. Therefore the female fitting must be stronger than the male fitting. Metals
are stronger than plastics. The female fitting has to be metal and the male fitting plastic.
Please note that mixing metal and plastics is not highly recommended and should be avoided if possible.
=================================================================================

Also, plastic expands/compresses with temperature variations of the engine area.

Seems like precision is essential when performing this fix.
Do "not" over-tighten or crack she goes.

Hmmm...

aptoslexus

[QUOTE=YLK;10208883]I have the same problem. Was about to start the repair after
buying the brass male barb hose fitting until
I found the following plastic knowledge base article...

Can you thread plastic and metal NPT fittings together?
www.usplastic.com/knowledgebase/article.aspx?contentkey=803
=================================================================================
To be able to thread plastic and metal fittings together the male fitting has to be plastic and the female fitting has to be metal.
When fittings with a tapered thread such as NPT are tightened the male fitting is compressed and the female fitting is stretched
(tensile stress). In general most materials have a higher compressive strength then a tensile strength. This is why the female
fitting is the one that will crack when over tightened. Therefore the female fitting must be stronger than the male fitting. Metals
are stronger than plastics. The female fitting has to be metal and the male fitting plastic.
Please note that mixing metal and plastics is not highly recommended and should be avoided if possible.
=================================================================================

Also, plastic expands/compresses with temperature variations of the engine area.

Seems like precision is essential when performing this fix.
Do "not" over-tighten or crack she goes.

Hmmm...[/QUOTE}

Well, you're not joining a metal and plastic npt fitting. The plastic on the resonator box is quite sturdy. I haven't had any problems with the fix. I suppose you could substitute a plastic fitting, but it might be more of a challenge to install.