underbody overhaul

[DustyDisco]

Well its finally time to give the disco a much needed underbody overhaul.

Rust has been creeping over the axles etc, the inside of the chasis rails are jammed full of mud, the suspension bushes are all stuffed,inlcuding the a-frame bush which has split, plus the brakes wont pass the next rego check - due in a week...

The disco is 18 years old though, so there is nothing to complain about :)

To get things started I dropped both of the long range tanks today - and found the cavity between the tank and the floorpan solid with crud:eek:.

No serious rust anywhere, but it is so filthy that its off to the truck wash this week for an underbody steam clean.

Then it will be POR-15 on all the steel other than the floorplan ( a coat of bitumen paint will go on the floorpan), cavity wax into the chasis rails, followed by new superpro bushes all round, new cranked trailing arms for the 3 inch spring lift, POR- 15 on the long range tanks, wack them back into place, new brake pads and then off to rego.

Should keep me busy for the next few weekends.

Just a shame that no one will ever get to see all that work once its done:D

[MMEJ]

I'm sure you're aware but be careful on the lift, WRT the steering arm's, flexy brake pipes, shock length, length of prop shaft, angle of the 'A' frame, etc.

Don't go mad with the hard bushes as they not only transmit noise into the body of the D1 but put a good deal of strain into the chassis where the arms (etc) mount, it's not unknown for the chassis to crack IWO these bushes. As a rule of thumb only use the hard bushes on the axel side of things and keep the OEM bushes next to the chassis.

Also don't go mad with the body underseal as you can trap moisture in and cause greater problems in a few years time. Use a soft underseal as this helps reduce stone chips to the paint system.

[DustyDisco]

thanks MMEJ,

sadly I have already purchased the Superpro bushes....for the price I paid it would be a shame to shelve them in favour of OEM.....from what I had read to date, superpro was superior to other poly bushes, hence why I went that way.

However, thanks for you advice and I will look further into this now - would appreciate any one elses experience on that topic also.

Today I spent 2 hours at the truck wash steam cleaning the underbody and engine bay - it took an hour to get all of the dirt out of the chassis rails:eek: yep, 30 minutes each rail with a high pressure hose in and out of all the holes to flush out the gunk.....the mud under the disco at the end was an inch deep in places when we were done:D

This weekend I will be prepping for the first coat of POR-15....

EDIT: I have had another look through many threads discussing superpro bushes, many people have used them at the chassis with no problems - I think I will be OK. There are however, many comments about problems arising with poor quality poly bushes used at the chassis, but these are different to superpro

[DustyDisco]

I'm sure you're aware but be careful on the lift, WRT the steering arm's, flexy brake pipes, shock length, length of prop shaft, angle of the 'A' frame, etc.

Yep, I have gone to 3 inch springs/ shocks....already have longer brake pipes, it may require a wide angle prop shaft...and with the spring lift in, castor is now .05 degrees, it should be 3.0 degrees.... I will be putting in 3 degree radius arms to compensate....I am also looking at slotting the swivels....

the whole suspension lift thing is really because I wanted a project....to be honest, I would tell people to stay with a 2 inch lift as you are right - going over 2 inches brings in all sorts of other complications.


Also don't go mad with the body underseal as you can trap moisture in and cause greater problems in a few years time. Use a soft underseal as this helps reduce stone chips to the paint system.

I am taking my time with this job - I am not using a bitumous sealer on the chassis rails etc, I am using POR-15, which is a paint - no chance of blocking the holes in the chassis rails with it, so it wont lead to any moisture trap problems, but thanks for the advice.

[Tombie]

You'll be fine with Superpro anywhere.

The "other" brands aren't up to scratch.

[DustyDisco]

spent about 5 hours under the disco today with a scrubbing brush and a spray bottle with 'marine clean' the recommended degreaser for use with the POR15 paint system.

Holy smokes.....it's a bloody big job - even after going to the truck wash for a steam clean it takes a lot of work to prep before painting...but all of the surface rust I have found all over the underbody tells me this job was well overdue.

One more day of degreasing to go, then I can start with the 'metal ready'....then onto the POR-15 - I think I will be spending the next month of weekends in the garage under the disco, have to laugh about it really:D

[nicho]

at least yours fits in the garage i have to settle for a driveway of rock instead of the concrete due to low roof on the garage and high lift on the disco. I'm stuffed if i have any major works to do to it:cool:

[DustyDisco]

at least yours fits in the garage i have to settle for a driveway of rock instead of the concrete due to low roof on the garage and high lift on the disco. I'm stuffed if i have any major works to do to it:cool:

LOL, mine is the same actually, lucky I now have a carport that I rent which it fits under.

It was a crackup when I put the larger springs in, I did it in the garage, which has a four meter high roof, only to find I had to air down the tyres to near flat in order to get out 2 metre door:Rolling:

[nicho]

Lol I left my stockies on until I got it out of the garage. Now I'd have to remove my roofrack and put the stockies back on if I wanted to get it inside. Lucky for me mine was an offroad virgin when I got it so it's still A1 underneath after a jet blast. Keep us up to date with what your doin mate I'd like to know if it makes a difference when cleaning up after run. Any time saved is a bonus for me these days

[DustyDisco]

Rear axle and chassis rails have now been repainted, so I got the QT trailing arms with Superpro bushes in today...despite the driving rain and wind.

There is abig difference from the standard 'noodle' arms :D

I found that the rear axle moved forward about 2 inches with the old arms out, so I had to rig up my jack and basically push the axle back into place and then use the bottle jack to seat the trailing arm into the axle mount properly..

https://www.aulro.com/afvb/images/imported/2011/05/13.jpg

[DustyDisco]

This is the before paint photo...axle has been cleaned, sanded, rust converted..it took hours....I will post the after phots tomorrow;

https://www.aulro.com/afvb/images/imported/2011/05/9.jpg

..Shiny and black...that wont last long :) (you can see the new trailing arms in place also)
https://www.aulro.com/afvb/images/imported/2011/05/10.jpg

[DustyDisco]

ON to the front axle now...started to de-greased it this morning...this photo gives you an idea of the state of things underneath - nothing more serious than surface rust, but high time to sort it out.https://www.aulro.com/afvb/images/imported/2011/06/1327.jpg
Once it is de-greased, rust converted and painted, on will go a new set of suspension bushes and 3 degree QT cranked radius arms.

[DustyDisco]

aaa

[DustyDisco]

Disapointed today to find that the POR-15 paint has failed on the cast metal of the rear dif. I followed the instructions meticulously, degrease with marine clean, wash and allow to dry, then coat with metal prep, then wash again and allow to dry, then two coats of POR-15.

In many sections of the diff the paint just peels off with bit of a scratch with a spatula- no trouble, it would not stand up against repeted stones, mud etc....very unhappy about this. It is supposed to bond and cure within 96 hours..it has been on for almost a month now.

It has also failed in 1 or two very small places on the seams of the rear axle, but not as bad as the almost complete failure on the cast metal.

Anyone considering using POR-15, at this point I would advise against using it on cast metal components...I would be reluctant to recommend anyone use it at all now though...unitl I re coat and see what happens.

I will be following this por-15 coating with Dynax UB, an underbody wax - in hindsight its possible that just using a normal enamal underbody paint, followed by Dynax UB, would have been fine.

Anyway, I will re-treat the sections that failed first time aroud and report back in a few weeks.

[ade]

I only ever high pressure wash the underneath then underbody wax the the lot, I also use old sump oil in the cavities under there, mainly the chassis rails and sills, not a sign of rust despite alot of beach driving and heaps of rock mud offroad, I have had excellent results with POR15 on a classic car I restored and used almost daily but not on cast metal.

[DustyDisco]

HI Ade,

Yes, I am just going to remove all the por 15 paint off the cast section of the diff housing and just re-test a small section before I re coat the whole thing with por 15 again.

If the test section fails a second time, it will just get Dynax UB under body wax.

In hindsight I probably could have got away with a good clean, a rust converter and just the dynax under body wax.... the POr 15 had definitely made this a longer ( much, much longer) job.:D

[DustyDisco]

Started cleaning the long range tanks today. Started out looking like this;

https://www.aulro.com/afvb/images/imported/2011/06/976.jpg https://www.aulro.com/afvb/images/imported/2011/06/977.jpg https://www.aulro.com/afvb/images/imported/2011/06/978.jpg

Ended up looking like this;

https://www.aulro.com/afvb/images/imported/2011/06/979.jpg https://www.aulro.com/afvb/images/imported/2011/06/980.jpg


Tomorrow is metal ready/ rust conversion and then Monday is the first coat of POR-15.

[DustyDisco]

Well, after cleaning and rust prepping the long range tanks, I then painted all the bare metal bits with 2 coats of Por-15, waited a week and today put on the coat of primer over the whole lot. https://www.aulro.com/afvb/images/imported/2011/06/668.jpg https://www.aulro.com/afvb/images/imported/2011/06/669.jpg
Next up, two coats of Por-15, followed by two coats of Dynax. Hopefully by then, my new radius arms have turned up from the UK,one of these days I will get the disco back on the road.

[nicho]

Your far too patient this is mud time. It's time to get her dirty. Put her back together take her for a run up to a nice muddy track and sink the boot in. Your missing out on the fun season

[DustyDisco]

Your far too patient this is mud time. It's time to get her dirty. Put her back together take her for a run up to a nice muddy track and sink the boot in. Your missing out on the fun season

So true:D but the problem is its out of rego and I am waiting for parts from the UK...going to do this once and do it right :D

[DustyDisco]

Well, the work continues...new radius arms, long range tanks finally painted and put back in, new bushes in the radius arms..painted the front axle..here are a few snapshots;

https://www.aulro.com/afvb/images/imported/2011/07/954.jpghttps://www.aulro.com/afvb/images/imported/2011/07/955.jpghttps://www.aulro.com/afvb/images/imported/2011/07/956.jpg
https://www.aulro.com/afvb/images/imported/2011/07/957.jpg

the work continues, still to go - new rear discs and pads, finish off the underbody clean and re wax, continue to wash dirt out of the chassis rails....new bump stops...etc

[TimmyA]

Where did you get these QT rear arms and bushes from???

Timmy

[nicho]

Where did you get these QT rear arms and bushes from???

Timmy

www.qtservices.co.uk is where I got mine I think you can get them from rovercraft as well and I'm sure others will tell you other suppliers

[DustyDisco]

Where did you get these QT rear arms and bushes from???

Timmy

Yep, Nicho is right, I got the 3degree radius arms and trailing arms from qt services in the UK.

The bushes are superpro bushes - I got them from a supplier in Australia www.wholesalesuspension.com.au/superpro.html (http://www.wholesalesuspension.com.au/superpro.html)

All other parts - brakes, pads, etc came from paddock spares also in the UKwww.paddockspares.com/ (http://www.paddockspares.com/)

[nicho]

Dusty all this attention your giving the underbody I'm thinking the first time you see mud on a track your gonna hit the skids and think twice!
But I must say it's all looking very nice and your going to love the ride with those radius and trailing arms. Mine feels like it's walking over rough terrain. It feels magic compared to the standard arms

[DustyDisco]

Dusty all this attention your giving the underbody I'm thinking the first time you see mud on a track your gonna hit the skids and think twice!
But I must say it's all looking very nice and your going to love the ride with those radius and trailing arms. Mine feels like it's walking over rough terrain. It feels magic compared to the standard arms

hehe, yes mate, that has crossed my mind:D got the day off work tomorrow, so the new rear discs and pads are going in, along with the new stone shields, new rear bump stops....hopefully done by lunchtime or early arvo and then its down to the mechanic for rego and then :burnrubber:..fingers crossed, after 2 months it will be back on the road

[nicho]

Excellent news mate let us know how it all goes. Always like hearing good news stories

[DustyDisco]

not there yet Nicho....got the new rear discs in, then discovered that the new rear trailing arms can strike on the rear edge of the long range tanks at certain angles....have to do a bit of a mod this weekend...close.....getting close :D

[bell1975]

Looks like you've been busy mate.

Can you please let me know where you found the best place to source the Dynax UB or Dynax S50 from? I'm about to do the underbody of my Disco 2. Dinitrol was my 1st choice but it won't be in the country for 8 weeks and I need this job done before that.

The price on the PPC website shows a 750ml can is $50. The Dinitrol is $20 or so for 1 litre...

The 750ml can will give a continuous spray for approx 5 minutes.

Did you or are you planning to do the whole underbody with the stuff?

Thanks.

[chazza]

Disapointed today to find that the POR-15 paint has failed on the cast metal of the rear dif.
I will be following this por-15 coating with Dynax UB, an underbody wax - in hindsight its possible that just using a normal enamal underbody paint, followed by Dynax UB, would have been fine.


You are the second person on AULRO that I know of who has had trouble with it.

I have done a 12 month field-trial with Penetrol on rusty steel and of the four products I tried, it was the only one that worked perfectly - after 12 months in the weather no new rust has appeared at all!

Cheers Charlie