Ls400 Mk 3 Power Steering Hose To Pipe Leak

Colin M · March 14, 2015

I have a slight leak at the bottom of the hose where it joins the metal pipework that runs in front of the radiator and then back again. It is the pipe nearest to the radiator – the one on the right in the photo.

My first thoughts are to change the hose to see if this stops the leak. I have tried a jubilee clip on the end of the hose to see if this will stop the leak but it does not and actually makes it worse!!

Lexus unhelpfully do not do the hoses as a separate item and they come as part of the upper section of pipework (i.e. the pipework that is connected to the top of the hoses). The internal diameter of the hose is 10mm and the external diameter is 17.5mm.

As ever, I would appreciate any advice before proceeding further.

In particular:

1. Has anyone replaced one of these hose and, if so, where did you get it from?

2. Am I correct in thinking that the hose and the pipework in front of the radiator is on the low pressure return side of the power steering system and not the high pressure delivery side?

3. Does anyone know what level of pressure the pipe needs to be able to withstand?

4. If and when the hose is replaced and there is some fluid loss, is it necessary to bleed air out of the system and, if so, how is this done?

Many thanks in anticipation of some help.

Ruud · March 14, 2015

A common area to leak. It is also the pipe itself that causes the leak. These usually have very tiny holes in them due to rust which also causes the hose not to fit properly anymore. It is indeed the low pressure side of the PS system and, in case of fluid loss, a simple top up and turning the wheel to full lock both ways, several times, will bleed the system.

Malc · March 14, 2015

hey, somewhere on here recently ( well last year now ) mine went and I replaced the front piece with the standard plumbers copper tube, funny diameter tho but cost £3 for the length ( to bend over ). That didn't solve the problem as the leak came from the rotten steel conglomeration of pipes just below the power steering box.... further up.

My indy did the job with appropriate flexi pipes and fixed the whole caboodle for me .......... . to give another 19 years life I hope.

Cost me about £100 all-up with his labour at £30 an hour.

Get it done before it just collapses on you, once it starts then it will become catastrophic, the old steel pipes just have rusted through by now.

Malc

Malc · March 14, 2015

......... my post was on summat like " catastrophic loss of power steering fluid "

Malc

cruisermark · March 14, 2015

here is the original post Malc mentioned:

http://www.lexusownersclub.co.uk/forum/topic/90341-catastrophic-loss-of-power-steering-fluid/

Colin M · March 14, 2015

Hi guys

Thanks for your quick and helpful replies.

I am in the process of trying to source a replacement hose as a first step. I have been looking online and have a few leads to follow up after the weekend. I will then report back on progress (or lack of it ...).

I think, as well as a new hose, I will probably replace the steel pipe in front of the radiator with 10mm copper tubing like others have done.

Hopefully a new hose and pipework should sort the problem.

Thanks a lot.

Colin

Malc · March 14, 2015

Colin hi, regrettably, I think you are unlikely to solve the problem with a piecemeal solution.

The mild steel construction of both the front pipe and the gubbins coming down to it has perished / rusted with effluxion of time, either imminent or shortly.

Sadly I think you will find the design fault ( well if you can call it that after 20 years nearly ) will produce a likely catastrophic loss of pas fluid at some time or other.

Wish you well with whatever solution you decide upon. Best wishes.

Malc

Colin M · March 14, 2015

Hi Malc,

Thanks, and I will certainly check out the state of the pipe work further up where it comes into the top end of the rubber hoses.

As you say, a piecemeal fix in one section will not be much good if there are pending problems elsewhere. I will give the whole system a good check over.

If I find any useful info I will of course post up on the thread so that it is available to all.

Thanks again, and all the best

Colin

Colin M · March 29, 2015

The leak at the bottom of the hose turned out to be due to the end of the power steering cooling pipe breaking off inside the hose. This can be seen if you look at the pipe in the bottom of the photo, which has only one bright metal end and not two as with the pipe in the middle, which is a very good original pipe which Rudy kindly sold to me. The other bright (or perhaps not so bright) broken off end is inside the old hose which can be seen in the photo.

I have had a couple of replacement copper pipes bent to shape by my plumber, using Rudy’s pipe as a template. One of these can be seen at the top of the photo (which I will put on my other LS400 this summer) and the other is on the car which had the leak. I have fitted two new hoses, cut about half an inch longer than the originals so there was enough pipe inside the hose to use both the original clamp and a jubilee clip at the end of the hose. This was a ‘belt and braces’ approach to minimise the risk of any leak, as there is no knibbed/lipped section near the end of the pipe which ensures a tight fit with the hose. There are no leaks and this seems to have worked fine. I filled the cooling pipe with fluid through the front hose before connecting the hose to minimise air locks. The pump did ‘howl’ quite a bit when I started the car but keeping the fluid topped up and moving the wheels from side to side repeatedly eventually got rid of any trapped air. All is quiet now.

Thanks to all for your help – much appreciated.