Rear sill rusty - Page 2

Arctic · 5th September 2018, 19:15

Quote:

Originally Posted by suzublu

It's a dirt trap in behind the liner. Mine was full of dirt & after cleaning it out, I found this

Quote:

Cleaned it back to metal, undersealed & repainted. What I do every year is wash behind all the liners, remove jacking pads & spray Dinitrol inside all the cavities, including the drain holes.

Hi Ron.
You were lucky there it had not eaten it's way through, were the under side parts ok where you jack the car up? sadly I was not so lucky

1

2

Corroded both sides at the rear.

3

My temporary fix for the Nano meet

both out of one piece of metal, worked into shape

4

suzublu · 5th September 2018, 19:42

Ouch!!! That looks bad Steve

Fortunately I caught mine before too much damage

Noticed a few ginger bits in the paint & when I scraped back found just metal, hadn't got as bad as yours, dodged a bullet methinks

trikey · 5th September 2018, 19:44

Quote:

Originally Posted by DRWMGTF

Nottingham!

Same difference...

Bit like Sunderland & Newcastle

Rickshaw · 5th September 2018, 20:59

The question was raised as to the source of the water rotting the sill rear. I VERY much suspect the Chrome finisher strips running along the cars and especially over the rear wings.
When I bought one of my 75’s I found a considerable boot leak . Naturally , I first cleaned and treated / sealed the rear window grips ( see excellent How to by Rich) . Then I turned to the Finisher Strips and traced the source to the associated grips / holes. I forced the finishers away from the car bodywork ( actually used Costa Coffee wooden stirrers !) and then applied thick Silicone Sealant all behind the chrome strips . Killed the boot leak dead! Now I note that some of the finisher strip grips / holes lay directly above the when arches / Rear jack points. I have now repeated the Silicone down the entire car length behind the finishers. With regard to the :-
• Sills , I now have them thickly internally coated with Dinitrol Wax
• Jack points , I have lifted the rubbers , removed any rust on the plinth just above them , then applied rust converter , then Epoxy Mastic and , finally a thick layer of Dinitrol. Then , off course , replaced the rubber seal.
If a couple of finisher grip /holes can flood a boot think what they can do with water running down into a sill ?
Any observations welcome.

Sonic ZS · 5th September 2018, 23:16

It's completely normal for water to enter the internal cavities of a car bodyshell (there are simply too many access points for manufacturers to be able to seal everything completely). Couple that to the condensation that will naturally occur on the inside of panels in the winter and you can see it's inevitable that damp will get inside and run to the bottom, due to gravity.

There has been plenty of discussion about why the rear sills on 75/ZT rot out and having completed quite extensive repairs previously on my Tourer, my own thoughts are as follows:

Firstly, there is a drain hole at the rear of the sill, so as long as this isn't blocked, water should eventually escape. However, just ahead of this is the internal jacking bracket. Surprisingly, this is welded to the vertical part of the inner sill, but NOT to the flat lower section of the outer sill. Here, it just rests against it. This leaves a very small gap between the two (the outer sill being far thinner metal), but it's enough space for the water to collect between the two panels and not dry out.

Secondly, if the jacking pads are not fitted, the remaining (quite large) hole that's left in the sill, will allow water and mud that's thrown up to collect inside the internal jacking bracket. Unfortunately, the edges of this are turned up to increase it's strength but this then means that anything that's wet and corrosive will collect inside and can't get out.

Lastly, the rear section of sill (unlike the front jacking point, although these are starting to go on older 75's nowadays) are connected directly to the rear quarter panel. Any moisture that collects inside this panel (from trim clips, condensation, etc.) and is over the front half of the rear wheelarch, HAS to run into the rear of the sill before it can escape out onto the road - hence the back section gets more than it's fair share of moisture to deal with.

Personally, I'm a fan of leaving the jacking pads fitted to keep the worst of the muck spray out, but leaving them out in the hot summer months to allow warmer air to circulate and dry things out as. There are also various holes where wax/oil can be inserted - behind the arch liner, on the inner sill and from behind the sill chrome strip, so any thin rust prevention fluid that'll squeeze itself under the jacking bracket has got to be good news if the sills are dried out properly first.

It's always a shame to hear of good cars possibly being scrapped just because this small area is starting to rust. Younger members of this forum will not be aware of corrosion in the 70's and 80's, when you could end up spending your weekends welding on complete length sills (not just 12"

) and continuing on to add rear wheelarches, spare wheel wells, door pillar bottoms, inner door frames and skins, front suspension top mounts, front panels and even footwells that had tin plate pop-riveted on to cover the holes !

Just ask Oxford Blue about a certain green Renault 12 estate...

deltic08 · 5th September 2018, 23:55

Quote:

Originally Posted by Arctic

Hi Adrian.
You will not be alone with this problem, all owners should be checking around the jacking pads/points for any bubbling which is the first sign of rust occurring under the protective seal in that area.

For some reason there are no drain hole before & aft of these jacking points, I am also convinced because of this fact the jacking pads do not help

I could be wrong.

Only last week I decided to do my usual yearly under body check, ie check the rear upper arms brake pipes etc, I noticed that around the rear jacking points a slight bubbling & tiny rust line.

I then poked the area with a blunt tool and to my big surprise around the jacking point it gave way, the same test last year I did and that sill area was solid so it shows just how quick the rust can eat through the metal, now due to the up coming nano meet I have crudely repaired the area with some new metal after cleaning back to bare metal and treating it.

This will give me time to decide before the next MOT January as to do I have the sills repaired properly or do I call it a day on the car.

Hello Artic,
The jacking point is solid. I quickly checked as the car is jacked up currently with rear wheel off. It was caked in muck under the arch liner. I had removed the muck with a hose, wire brushed and rubbed down rust spots and put 3 coats of Hammerite on before I saw the sill. I was wire brushing the suspension when I noticed the sill.
The inner sill is solid so just going to cut metal patch to fit and Mig weld in. Just hoping I can match the paint as it is Posiedon flip paint.

deltic08 · 6th September 2018, 00:05

Quote:

Originally Posted by trikey

You need a trip to derby to see tom Hobbs .

http://www.tjhobbs.com

Hello Trikey,
I have checked out Tom Hobbs website but no pictures of completed spray jobs. Does he only panel beat?
Adrian

deltic08 · 6th September 2018, 00:27

Quote:

Originally Posted by Sonic ZS

It's completely normal for water to enter the internal cavities of a car bodyshell (there are simply too many access points for manufacturers to be able to seal everything completely). Couple that to the condensation that will naturally occur on the inside of panels in the winter and you can see it's inevitable that damp will get inside and run to the bottom, due to gravity.

There has been plenty of discussion about why the rear sills on 75/ZT rot out and having completed quite extensive repairs previously on my Tourer, my own thoughts are as follows:

Firstly, there is a drain hole at the rear of the sill, so as long as this isn't blocked, water should eventually escape. However, just ahead of this is the internal jacking bracket. Surprisingly, this is welded to the vertical part of the inner sill, but NOT to the flat lower section of the outer sill. Here, it just rests against it. This leaves a very small gap between the two (the outer sill being far thinner metal), but it's enough space for the water to collect between the two panels and not dry out.

Secondly, if the jacking pads are not fitted, the remaining (quite large) hole that's left in the sill, will allow water and mud that's thrown up to collect inside the internal jacking bracket. Unfortunately, the edges of this are turned up to increase it's strength but this then means that anything that's wet and corrosive will collect inside and can't get out.

Lastly, the rear section of sill (unlike the front jacking point, although these are starting to go on older 75's nowadays) are connected directly to the rear quarter panel. Any moisture that collects inside this panel (from trim clips, condensation, etc.) and is over the front half of the rear wheelarch, HAS to run into the rear of the sill before it can escape out onto the road - hence the back section gets more than it's fair share of moisture to deal with.

Personally, I'm a fan of leaving the jacking pads fitted to keep the worst of the muck spray out, but leaving them out in the hot summer months to allow warmer air to circulate and dry things out as. There are also various holes where wax/oil can be inserted - behind the arch liner, on the inner sill and from behind the sill chrome strip, so any thin rust prevention fluid that'll squeeze itself under the jacking bracket has got to be good news if the sills are dried out properly first.

It's always a shame to hear of good cars possibly being scrapped just because this small area is starting to rust. Younger members of this forum will not be aware of corrosion in the 70's and 80's, when you could end up spending your weekends welding on complete length sills (not just 12"

) and continuing on to add rear wheelarches, spare wheel wells, door pillar bottoms, inner door frames and skins, front suspension top mounts, front panels and even footwells that had tin plate pop-riveted on to cover the holes !

Just ask Oxford Blue about a certain green Renault 12 estate...

The rubber pad was missing so I suspect some damage was from that. My other ZT/ZTTs are soaked in Dynax S50 using the lance to reach into box sections. Done annually. Haven't got round to doing this one yet. Only had it 4 weeks. Gradually working my way around. A lot to put right externally, mostly paint scratches and stone chips and a very rusty slam panel under bonnet. I suspect it has been stored or lived near the seaside. Certainly not loved as the door edges and hinges were filthy including B pillar and tailgate edges.
Will check the trim for leaks as you suggest.

Dawn · 6th September 2018, 06:01

Tom will paint sills and bits but not full resprays. He says a big cause of the corrosion is a foam pad in the sill. He removes it when doing the job. He charges £100 a side for sills like Arctics. My Cowley was worse and that was the price. She will be at the Nano Satvif anyone wants a peek!

deltic08 · 6th September 2018, 09:59

Quote:

Originally Posted by roverbarmy

I am convinced that the large cupped jack tops, as used by most garages, when used at the jacking points, actually lift around the reinforced section, distorting the metal and break the paint seal. Once the metal is exposed (either internally or externally) rusting is inevitable. I have had all four jacking points repaired with a larger and thicker sill section, supported by the inner reinforcing section. The inside of the sill is now coated (annually) with Bilt Hamner with added Waxoyl, applied using the 360 degree flexible lance which is supplied with the tin, via the drain holes and the holes in the ends of the sills (which have a rubber bung in them), accessible by removing the bottom of the arch liners. I use clear protectant for the doors, bonnet and boot cavities using the same principal.

Hello Roverbarmy,
I usually use Dynax on my box sections but I have only had this ZTT 4 weeks and not had chance yet doing other things to it. It is good stuff. I have just ordered 2 cans to do it.

Why do you add Waxoyl to Dynax?

Adrian

5th September 2018, 20:59	#14
Rickshaw Loves to post Rover 75 Tourer, 2 X75 Saloon , MGTF Sunstorm Join Date: Jan 2013 Location: Guildford Posts: 380 Thanks: 497 Thanked 172 Times in 93 Posts	Likely source ? The question was raised as to the source of the water rotting the sill rear. I VERY much suspect the Chrome finisher strips running along the cars and especially over the rear wings. When I bought one of my 75’s I found a considerable boot leak . Naturally , I first cleaned and treated / sealed the rear window grips ( see excellent How to by Rich) . Then I turned to the Finisher Strips and traced the source to the associated grips / holes. I forced the finishers away from the car bodywork ( actually used Costa Coffee wooden stirrers !) and then applied thick Silicone Sealant all behind the chrome strips . Killed the boot leak dead! Now I note that some of the finisher strip grips / holes lay directly above the when arches / Rear jack points. I have now repeated the Silicone down the entire car length behind the finishers. With regard to the :- • Sills , I now have them thickly internally coated with Dinitrol Wax • Jack points , I have lifted the rubbers , removed any rust on the plinth just above them , then applied rust converter , then Epoxy Mastic and , finally a thick layer of Dinitrol. Then , off course , replaced the rubber seal. If a couple of finisher grip /holes can flood a boot think what they can do with water running down into a sill ? Any observations welcome.

5th September 2018, 23:16	#15
Sonic ZS Posted a thing or two 75 Conn CDT Tourer, 75 Conn SE V6, 75 Conn V6, 75 Conn CDTi Tourer, ZS 180 Join Date: Jan 2014 Location: Devon Posts: 1,986 Thanks: 1,287 Thanked 963 Times in 534 Posts	It's completely normal for water to enter the internal cavities of a car bodyshell (there are simply too many access points for manufacturers to be able to seal everything completely). Couple that to the condensation that will naturally occur on the inside of panels in the winter and you can see it's inevitable that damp will get inside and run to the bottom, due to gravity. There has been plenty of discussion about why the rear sills on 75/ZT rot out and having completed quite extensive repairs previously on my Tourer, my own thoughts are as follows: Firstly, there is a drain hole at the rear of the sill, so as long as this isn't blocked, water should eventually escape. However, just ahead of this is the internal jacking bracket. Surprisingly, this is welded to the vertical part of the inner sill, but NOT to the flat lower section of the outer sill. Here, it just rests against it. This leaves a very small gap between the two (the outer sill being far thinner metal), but it's enough space for the water to collect between the two panels and not dry out. Secondly, if the jacking pads are not fitted, the remaining (quite large) hole that's left in the sill, will allow water and mud that's thrown up to collect inside the internal jacking bracket. Unfortunately, the edges of this are turned up to increase it's strength but this then means that anything that's wet and corrosive will collect inside and can't get out. Lastly, the rear section of sill (unlike the front jacking point, although these are starting to go on older 75's nowadays) are connected directly to the rear quarter panel. Any moisture that collects inside this panel (from trim clips, condensation, etc.) and is over the front half of the rear wheelarch, HAS to run into the rear of the sill before it can escape out onto the road - hence the back section gets more than it's fair share of moisture to deal with. Personally, I'm a fan of leaving the jacking pads fitted to keep the worst of the muck spray out, but leaving them out in the hot summer months to allow warmer air to circulate and dry things out as. There are also various holes where wax/oil can be inserted - behind the arch liner, on the inner sill and from behind the sill chrome strip, so any thin rust prevention fluid that'll squeeze itself under the jacking bracket has got to be good news if the sills are dried out properly first. It's always a shame to hear of good cars possibly being scrapped just because this small area is starting to rust. Younger members of this forum will not be aware of corrosion in the 70's and 80's, when you could end up spending your weekends welding on complete length sills (not just 12" ) and continuing on to add rear wheelarches, spare wheel wells, door pillar bottoms, inner door frames and skins, front suspension top mounts, front panels and even footwells that had tin plate pop-riveted on to cover the holes ! Just ask Oxford Blue about a certain green Renault 12 estate... __________________

5th September 2018, 19:42	#12
suzublu This is my second home rover 75 1.8 vvc club se wedgwood blue Join Date: Aug 2009 Location: Seaton Carew Posts: 26,912 Thanks: 65 Thanked 7,142 Times in 4,642 Posts	Ouch!!! That looks bad Steve Fortunately I caught mine before too much damage Noticed a few ginger bits in the paint & when I scraped back found just metal, hadn't got as bad as yours, dodged a bullet methinks

6th September 2018, 06:01	#19
Dawn I really should get out more....... MG ZT 180+ auto Join Date: May 2016 Location: Ilkeston, Derbys Posts: 2,743 Thanks: 285 Thanked 1,128 Times in 504 Posts	Tom will paint sills and bits but not full resprays. He says a big cause of the corrosion is a foam pad in the sill. He removes it when doing the job. He charges £100 a side for sills like Arctics. My Cowley was worse and that was the price. She will be at the Nano Satvif anyone wants a peek!