Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > Technical Help Forum
Register FAQ Image Gallery Members List Calendar Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 3rd September 2019, 17:51   #1
DaylightRovery
Regular poster
 
Rover 75 Saloon

Join Date: Apr 2019
Location: Sunderland
Posts: 35
Thanks: 1
Thanked 17 Times in 1 Post
Default CDTI Undertray clips

Evening all.

My undertray is hanging down on my CDTI facelift contemporary. Half the clips are missing and as I dont have access to ramps it's a pain in the hoop to get the central 2 bolts/clips.

2 questions.

1. Is the undertray really that effective? has anyone took theirs off completely and the car suddenly rusted from bottom up??

2. I can find the clips on ebay for the front bumper. They're the long screws with what appears to be 1 incredibly course thread on the end. Are the 2 central screws the same as these?? as they completely missing and my undertray is hanging like a hammock!.

Cheers all.
DaylightRovery is offline   Reply With Quote
Old 3rd September 2019, 18:04   #2
suzublu
This is my second home
 
suzublu's Avatar
 
rover 75 1.8 vvc club se wedgwood blue

Join Date: Aug 2009
Location: Seaton Carew
Posts: 26,880
Thanks: 65
Thanked 7,142 Times in 4,642 Posts
Default

What you need matey https://www.dmgrs.co.uk/collections/...0050-kzm000050
suzublu is offline   Reply With Quote
Old 3rd September 2019, 18:32   #3
ceedy
This is my second home
 
ceedy's Avatar
 
All Trophy Blue ,ZT260#50 , ZT CDTI Auto, ZR105+ and 1.8T Firefrost spoiling the Set .

Join Date: Nov 2006
Location: Nr Sherborne But in Somerset..
Posts: 6,061
Thanks: 916
Thanked 1,214 Times in 768 Posts
Default

Sorry those are hopeless..;

Had some .too soft and just jam up .

And single slot
Well that's my experience .
__________________
The Three Bloo's
Wifey's Zr105, MY CDTI & 260 #50 and
Number One sons 1.8T in Firefrost
When I were a lad
Zero to 142 in 10.25 secs at the Pod on my Blown Norton.
210 Kart Champ in 70's

ceedy is offline   Reply With Quote
Old 3rd September 2019, 18:33   #4
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,265
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
Default

Hello Robert,

To answer your questions:
Quote:
Originally Posted by DaylightRovery View Post
1. Is the undertray really that effective?
Do you think that a car manufacturer would go to the trouble and expense of making and fitting a component that wasn't effective?

As I understand it, the undertray performs two functions:
  • Aerodynamics. It smooths airflow under the car which the theory probably tells us improves roadholding.
  • Protection. It stops rainwater splashing upwards causing corrosion and electrical faults.
Quote:
Originally Posted by DaylightRovery View Post
2. I can find the clips on ebay for the front bumper. They're the long screws with what appears to be 1 incredibly course thread on the end.
The best fittings are not found on e-bay. They are the genuine MG Rover Dzus fasteners. These are released with a 180˚ turn of a Posidriv bit. The spigot is retained on the undertray with a nylon washer. Omitting these washers is the main reason why the fasteners are lost and the undertray hanging down.

I have the OEM Dzus fasteners on my car. I don't agree that the parts offered by DMGRS are superior. They require many turns because they're effectively screws. Unless you have a 4 post lift, that isn't an advantage. A 180˚ twist wins every time.

Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.
SD1too is offline   Reply With Quote
Old 3rd September 2019, 18:50   #5
HarryM1BYT
This is my second home
 
HarryM1BYT's Avatar
 
75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD

Join Date: May 2010
Location: Leeds
Posts: 17,273
Thanks: 2,160
Thanked 2,061 Times in 1,586 Posts
Default

Quote:
Originally Posted by SD1too View Post
The best fittings are not found on e-bay. They are the genuine MG Rover Dzus fasteners. These are released with a 180˚ turn of a Posidriv bit. The spigot is retained on the undertray with a nylon washer. Omitting these washers is the main reason why the fasteners are lost and the undertray hanging down.
I managed to get some from ebay, which did work fine, they were just slotted instead of posidrive and bright plated, instead of black.

A couple of the spring nuts they screw into had failed on the sub-frame and they came complete with the nuts, so I replaced those two as well. They needed a bit of squeezing up, to get the nuts to properly stay put on the sub frame.

They do really need the plastic retaining washers to prevent fasteners getting lost. I made lots of them from a 4 pint plastic milk container, using a 25mm hole saw.


__________________
Harry

How To's and items I offer for free, or just to cover the cost of my expenses...

http://www.the75andztclub.co.uk/foru...40#post1764540

Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing.

I've taken a vow of poverty. To annoy me, send money.
HarryM1BYT is offline   Reply With Quote
Old 3rd September 2019, 19:01   #6
suzublu
This is my second home
 
suzublu's Avatar
 
rover 75 1.8 vvc club se wedgwood blue

Join Date: Aug 2009
Location: Seaton Carew
Posts: 26,880
Thanks: 65
Thanked 7,142 Times in 4,642 Posts
Default

Quote:
Originally Posted by ceedy View Post
Sorry those are hopeless..;

Had some .too soft and just jam up .

And single slot
Well that's my experience .
Quote:
Originally Posted by SD1too View Post
Hello Robert,

To answer your questions:

Do you think that a car manufacturer would go to the trouble and expense of making and fitting a component that wasn't effective?

As I understand it, the undertray performs two functions:
  • Aerodynamics. It smooths airflow under the car which the theory probably tells us improves roadholding.
  • Protection. It stops rainwater splashing upwards causing corrosion and electrical faults.

The best fittings are not found on e-bay. They are the genuine MG Rover Dzus fasteners. These are released with a 180˚ turn of a Posidriv bit. The spigot is retained on the undertray with a nylon washer. Omitting these washers is the main reason why the fasteners are lost and the undertray hanging down.

I have the OEM Dzus fasteners on my car. I don't agree that the parts offered by DMGRS are superior. They require many turns because they're effectively screws. Unless you have a 4 post lift, that isn't an advantage. A 180˚ twist wins every time.

Simon
Sorry chaps, can't comment on the quality of those linked, just wanted to give the OP an idea of what he needed
Personally, I have similar to these https://www.ebay.co.uk/itm/LANDROVER...cAAOSwux5YKbVA
suzublu is offline   Reply With Quote
Old 3rd September 2019, 19:42   #7
DaylightRovery
Regular poster
 
Rover 75 Saloon

Join Date: Apr 2019
Location: Sunderland
Posts: 35
Thanks: 1
Thanked 17 Times in 1 Post
Default

Cheers people, the under tray will stay as I supoose I wanted my own thoughts confirmed.

Suzublu many thanks. I dont suppose you know weather the 2 central fasteners use the litle gripper bit of metal or do they screw straight into a thread on the underside of the car??
DaylightRovery is offline   Reply With Quote
Old 3rd September 2019, 20:26   #8
roverbarmy
This is my second home
 
roverbarmy's Avatar
 
Roverless + 1.7D Sportage

Join Date: Aug 2014
Location: East Norfolk
Posts: 7,022
Thanks: 729
Thanked 2,021 Times in 1,449 Posts
Default

My 2000 V6 has an immaculate engine compartment (always had the undertray). My previous 2005 car had no tray and a rusty underside and corrosion showing on the alloy parts of the engine underside (before I treated it!). The V6 engine noise is quieter than the 1.8 was!
__________________
Oil in my veins!
roverbarmy is offline   Reply With Quote
Old 4th September 2019, 01:15   #9
BigRuss
Premium Trader
 
BigRuss's Avatar
 
75 CDT Tourer,2.5 Launch Saloon, Omipro MG/Rover (T4)

Join Date: Jul 2007
Location: Liversedge, West Yorkshire
Posts: 5,405
Thanks: 1,105
Thanked 1,340 Times in 661 Posts
Default

The standard undertray fittings are absolutely hopeless when the lugs for the Dzus fasteners corrode they don't hold, those LandRover ones are no better as they don't fit on some of the subframe fittings

What you really need to make the undertray secure are some of these instead of the standard clips:

https://www.ebay.co.uk/itm/M4-M5-M6-...S5sB70YEcXdGKA

M6 should do it combined with some M6 bolts and some suitable repair washers

It shouldn't come adrift then

My Volvo has them as standard for it's undertray and they do a far better job, they've never come adrift

Russ
__________________


Replacement Key Service
http://https://the75andztclub.co.uk/...d.php?t=244732
Full T4 Testbook diagnostics available.
Diesel ECU repair and replacement.
Options enabled or disabled as required.
Diesel X-Power 135 and 160bhp, Rover 1.8T 150 to 160
MG 160 V6 to 177 upgrades available
P.M. for details.

Last edited by BigRuss; 4th September 2019 at 01:27..
BigRuss is offline   Reply With Quote
Old 4th September 2019, 08:11   #10
SD1too
Doesn't do things by halves
 
SD1too's Avatar
 
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model.

Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,265
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
Default

Quote:
Originally Posted by BigRuss View Post
... when the lugs for the Dzus fasteners corrode ...
That's easily prevented with a dab of Waxoyl or grease as you would for any threaded fitting in a vulnerable location. Alternatively, renew the corroded part, they are available from X-Part or BMW.

The undertray will not come adrift if the nylon washers are used and the spigots lubricated and positively fitted.

Simon
__________________
"Whatever is rightly done, however humble, is noble."
Sir Henry Royce.
SD1too is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 01:25.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © 2006-2023, The Rover 75 & MG ZT Owners Club Ltd