1996 LS400 Project. Let the fun begin.....!

[Howplum]

Yesterday I thought I would change the fuel filter, which I had hoped would be straightforward, but unfortunately it was not.  I was able to undo and disconnect the banjo union on the inlet side, but although I could undo the gland nut on the outlet side the steel pipe would not budge, so presumably was corroded into position. I had read that quite a bit of fuel will leak out, and I ended up with about 1 litre.

For fear of causing a major problem by using too much force, I adopted the mantra "if it ain't broke don't fix it" and put everything back together again. Of course the sealing washers on the banjo union didn't like being disturbed, so I discovered there was a leak when the pump was turned on. I therefore had to undo the banjo union and replace the seals, although this time I ended up with about 7 litres of fuel! Eventually I did the job with petrol still coming out - very messy.

The next job, whilst I was under the car, was to replace the fill and drain plugs in the differential, which was straightfoward.

Whilst I was doing all that my instrument cluster arrived, which I was  looking forward to reinstalling. To my horror I discovered that the grey multipin connector had fallen down and was crushed by the steering column. Sods law dictates that it was the largect connector with around 20 wires. "Oh dear" I thought, although that's not what came out my mouth!

Clearly it's not usable, so my first thought is to try and get one from a breaker, although presumably it must be from a 1996 model, in case the wiring is different in previous and later models.

Any helpful ideas would be appreciated though.

[steve2006]

Ooops! I don’t have the Lexus electrical workshop manual for the series III LS400, you can buy the plug and contact inserts but given the present situation even with part numbers this would be difficult. I would get one out of a breaker as it’s not a common purchase. Just make sure the seller cuts the loom long so you can splice the wiring. Best method is solder and heat shrink.

[runsgrateasanut]

That's a nightmare Howard - good luck with sourcing that part etc.

I can tell you that my mechanic couldn't undo the Fuel Filter even on the second occasion I left the Car with him.

The pipe to front was immediately right angled and between parts so perhaps (?) looking at your photo, not so difficult to cut off and put a length of pipe in if the Nut gets mangled and has to be cut off. 

Third visit,  I gave him an American  tool which I thought might just work on undoing the Nut, and he succeeded.   

It was one similar to this set.  After he did the job I happened upon a single one on t'bay for a tenner and bought it for him as a gift. Holding on to my set !  

Must cut open the old filter to see what it looks like inside.  Been done more than a year ago. 

ps I have a length of tubing with Nut and 8mm compression joints, which i advertised on t'bay some time back. If interested I'll tell you more about the parts. 

https://www.ebay.co.uk/itm/Super-Wrench-Hawks-Beak-Grips-Set-Adjustable-Spanner-Trade-Quality-4pc/153689661329?hash=item23c89e1f91:g:TFkAAOSwEIBec1Eq

 

[Howplum]

Thanks Stuart,

The problem is not getting the gland nut undone but getting the pipe out of the filter. Presumably something to do with dissimilar metals.

I'm not sure what's on the end of the pipe, so have visions of having to replace the entire pipe if things go horribly wrong, hence my caution.

I was going to replace it on the basis of time, not mileage, which is only 79,000, but at the moment I'll put the job on the B list for the time being.

[runsgrateasanut]

Quite understand.  The pipe is flanged and the Screw in Nut (?) is very slightly flared so that no Washer is required but its the tighness of the fit that seals - I think I'm right in saying.   I did suggest my mechanic put PTFE tape at the outer area of the thread when installing the new filter to be doubly sure.

[ambermarine]

Years back my Mark 1 was serviced by Lexus in the first two years of my ownership ,the fuel filter change  came up in the service schedule and the service manager said they reserved the right to not touch it as the unions were corroded and from experience knew it was a nightmare.I reluctantly agreed and eventually forgot about it, the car eventually did 180k and I never had any trouble with the filter.

Just to be clear I am not advocating the omission of service requirements but if you know the history of your car and have never put derv or bad petrol in mixed with water etc then the filter should be fine and there is a filter on the fuel pump .

[Howplum]

Re. the damaged connector, it looks as though I have been lucky enough to find someone breaking a 1996 model and he has agreed to remove the connector from the loom, with plenty of wire still attached.

Although the connector has a locking clip underneath, it's clear that even with that slackened off the metal terminals are not designed to be removed.

I think I have two possible ways of attaching the replacement connector.

The first is to use heat shrink butt connectors on each of the 19 wires, but I feel the problem with that is using a large hot air gun in a restricted space, the close proximity of the wires to each other and working so close to the dashboard. The last thing I want to do is damage the dashboard!

The second, which I favour, is a couple of mini multiple connectors, such as these:

https://www.autoelectricsupplies.co.uk/product/41/category/7

They don't take up much room and a soldering iron is easier to manage in a restricted space than a hot air gun.

The safest option, with no heat risks, is to use individual crimp butt connectors, but I'm not sure how reliable they would be, long term. It's not a job I want to repeat, or to try and trace faults later down the line.

[fred81]

can you not remove the existing wires and pins with a molex removal tool? probably most of those can be salvaged - then you'd just need to solder the broken ones.

[Howplum]

Thanks Fred. I had thought of that idea, but wasn't quite sure how to do it. I have loosened one of the terminals in the connector and I see they are 2mm square with a small tab on one of the corner edge which engages with a small lip in the hole it fits into. I suppose the trick is knowing which is the correct tool.

Obviously your suggestion is more elegant, less risky and, with the right tool, easier.  I'm off to do some research.

[fred81]

well, you could also try with a hacksaw and see if you can break down the surround enough to remove all the pins easily, then they should just slide in the new body. id get marking each wire up first though!

[Howplum]

I could, but the replacement connector is used, so already the terminals and wires fitted.

I have made a note of the various wires, and taken pictures, especially as two of them are the same colour!

[Howplum]

Well, I'm struggling to find an appropriate terminal removal tool. Most terminals seem to have barbs which are pushed flat by the tool, but due to the unique Lexus/Toyota design it is difficult to see how the tab can be bent over to enable removal.

I have ordered a couple of the multiple connectors I mentioned, but have done some research on crimped connections, for which there seems to an argument in favour of them over soldering:

"Why Crimping Outperforms Soldering for Cable Connections

For cable connections, crimping typically outperforms soldering for a few key reasons. First and foremost, cable connections last longer when they are crimped because they are protected from the intrusion of moisture, dirt and debris. Crimping tools are designed to create an air-tight seal between the cable and the connector. Therefore, moisture, dirt and debris won’t be able to reach the crimped cable. Soldering, unfortunately, doesn’t offer this same level of protection.

Crimping offers stronger, more reliable connections than soldering. Soldering uses heated metal to join the cable to the connector. Over time, this filler metal will degrade, which may cause the connection to fail."

I had always been under the impression they were a no no, but I noticed the existing terminal connections are crimped, not soldered.

Maybe....?

[ambermarine]

 Howard

To go back to the soldering method have you considered the combined heat shink / solder tube .I have seen these used and they are very effective .

Simply place both wires in the tube then heatgun the tube the solder melts and the tube shrinks creating a sterile joint if you use the correct narrow nozzle on the heat gun you will be able to precisely connect each wire without affecting others if you shield each wire.

[steve2006]

Not sure if this helps but gives the dimensions of the terminal removal tool.

[runsgrateasanut]

27 minutes ago, ambermarine said:

 Howard

To go back to the soldering method have you considered the combined heat shink / solder tube .I have seen these used and they are very effective .

 

Blimey, I learn something every day on this forum. Never new they existed.

[Howplum]

Thanks Steve, that looks promising, and simple enough to make. Could I trouble you for a picture of the next page please, which hopefully shows how to use it?

Howard

[Howplum]

1 hour ago, ambermarine said:

To go back to the soldering method have you considered the combined heat shink / solder tube .I have seen these used and they are very effective .

Yes Phil, I have. My son swears by them and I am sure they are very good, but I am a bit wary about parking a very hot air gun inside the instrument binnacle without potentially causing collateral damage to something less easy to fix, such as a wiring loom or the dashboard.

[ambermarine]

Howard

Forgive me if I sound a bit confused here but the connections will be made before you present this plug to the binnacle or am I missing something.

[Howplum]

Yes, I will be replacing the multiple connector before reinstalling the instrument cluster. However, there isn't a lot of room to park a hot air gun without the possibility of accidentally melting something!

My favourite option is to swap the terminals over, which appears possible, once I've acquired the knack.

[ambermarine]

OK  Howard thanks for the update.

[steve2006]

5 hours ago, Howplum said:

Thanks Steve, that looks promising, and simple enough to make. Could I trouble you for a picture of the next page please, which hopefully shows how to use it?

Howard

Here you go.

[Howplum]

Thanks Steve.

[Howplum]

I have managed to track down the technical document created by Toyota entitled "Terminal and Connector Repair - Terminal Replacement":

https://www.toyota-tech.eu/wire_harness_rm/RM06H0E.pdf

I will add a How to Guide, once I've tried it out.

Interestingly, Toyota recommend a simple crimped connection for wire repairs, which should then be wrapped in silicon tape, to prevent moisture ingress.

I am now awaiting the replacement connector from the eBay seller.

[ambermarine]

Howard thanks for linking the terminal guide it is a useful bit of kit.

[runsgrateasanut]

Link didn't open for me - said security risk. Will check my settings.