Rear suspension bolts RYP100150 - Page 4

Greeners · 27th May 2013, 15:19

why not take one into an engineering shop and get a "pros" view on it ....

steve811 · 27th May 2013, 16:44

Well, firstly, after 20 plus years as an aircraft engineer I probably know more than some of the so called "Engineers" I have met in engineering manufacture around here! Secondly I am 95% convinced the bolts I have chosen will be up for the job, I just want to know the original spec of the bolts I am replacing to confirm that. To do that I need access to a Rockwell machine to test the hardness of the material or a stress tester to give me the UTS of the original bolts!

I am happy that replacing the bolts with 12.9 bolts will be sufficient, and that socket head bolts on thick washers will not result in the heads "bedding in" to the bracket. What I would like to know is the original spec, on some suspension bolts Rover used 8.8 bolts and others 10.9, I don't have enough data to calculate the loading on these bolts so I am going for an over-engineered approach.

Greeners · 27th May 2013, 16:46

Quote:

Originally Posted by steve811

Well, firstly, after 20 plus years as an aircraft engineer I probably know more than some of the so called "Engineers" I have met in engineering manufacture around here! Secondly I am 95% convinced the bolts I have chosen will be up for the job, I just want to know the original spec of the bolts I am replacing to confirm that. To do that I need access to a Rockwell machine to test the hardness of the material or a stress tester to give me the UTS of the original bolts!

well thats me told

steve811 · 27th May 2013, 19:31

Sorry, that was not meant to appear belligerent!

Steve1966 · 27th May 2013, 21:51

Quote:

Originally Posted by Froggy-Mk2

The end of that screw has been specially machined, I wonder why ?

Looks part bleed nipple part self tapper - weird, especially at M12. What function is that conical end performing I wonder.

This bolt end design is to clear paint from the thread of the body side nuts, and the cone to help with alignment / starting the thread. It is commonly used by Rover on any nut that may see paint in the threads during the build process. A damaged thread in a captive or weld nut stops the line and isn't easy to rectify.
Steve

steve811 · 27th May 2013, 22:16

Thanks Steve, that confirms what I thought, the cone and the interrupted thread have no real significance now!

Froggy-Mk2 · 28th May 2013, 08:08

Quote:

Originally Posted by steve811

Thanks Steve, that confirms what I thought, the cone and the interrupted thread have no real significance now!

Makes sense now

steve811 · 1st June 2013, 15:19

Well, the bolts turned up on Tuesday and today I set about changing them. That's when I found out that the bolts do need to be flanged! The reason is that the high torque loading (100Nm) tends to bed in the head of the bolt into the relatively soft steel of the suspension bracket! I tried putting a washer underneath but that just dished under load, so I have ordered some really thick (5mm) thick washers to spread the point loading of the bolts. Until then the original bolts have gone back in!

Froggy-Mk2 · 1st June 2013, 16:51

Quote:

Originally Posted by steve811

Well, the bolts turned up on Tuesday and today I set about changing them. That's when I found out that the bolts do need to be flanged! The reason is that the high torque loading (100Nm) tends to bed in the head of the bolt into the relatively soft steel of the suspension bracket! I tried putting a washer underneath but that just dished under load, so I have ordered some really thick (5mm) thick washers to spread the point loading of the bolts. Until then the original bolts have gone back in!

But at least you have identified thread size and form plus length

and these seem pretty close - BMW bolts
http://www.ebay.co.uk/itm/BMW-Hex-He...item43b2edc633

VMax1000 · 2nd June 2013, 07:27

Quote:

Originally Posted by steve811

Well, the bolts turned up on Tuesday and today I set about changing them. That's when I found out that the bolts do need to be flanged! The reason is that the high torque loading (100Nm) tends to bed in the head of the bolt into the relatively soft steel of the suspension bracket! I tried putting a washer underneath but that just dished under load, so I have ordered some really thick (5mm) thick washers to spread the point loading of the bolts. Until then the original bolts have gone back in!

Proof that after 20 years in Engineering you can still learn something

Been there, done that

and still learning

27th May 2013, 15:19	#31
Greeners Moderator MG-ZTT Join Date: Mar 2007 Location: Ware, Herts Posts: 19,798 Thanks: 161 Thanked 1,249 Times in 1,036 Posts	why not take one into an engineering shop and get a "pros" view on it .... __________________ *David* Impecunity is the mother of ingenuity Useful how to's for common problems Car Of The Month Jan 2014 [SatNav Power Down] [Coolant Level] [SatNav Repair] [Diesel Non Starting] [Paint Codes] [Rear Light Seals] [Reversing Light Switch] [Bleeding Brakes][Sunroof Drain] [Early ZT's][Instrument Pack Diagnostics][ATC Diagnostics]

27th May 2013, 16:44	#32
steve811 Banned Rover 75 Tourer CDT Connoisseur SE Join Date: Dec 2010 Location: Newport Posts: 1,906 Thanks: 107 Thanked 299 Times in 206 Posts	Well, firstly, after 20 plus years as an aircraft engineer I probably know more than some of the so called "Engineers" I have met in engineering manufacture around here! Secondly I am 95% convinced the bolts I have chosen will be up for the job, I just want to know the original spec of the bolts I am replacing to confirm that. To do that I need access to a Rockwell machine to test the hardness of the material or a stress tester to give me the UTS of the original bolts! I am happy that replacing the bolts with 12.9 bolts will be sufficient, and that socket head bolts on thick washers will not result in the heads "bedding in" to the bracket. What I would like to know is the original spec, on some suspension bolts Rover used 8.8 bolts and others 10.9, I don't have enough data to calculate the loading on these bolts so I am going for an over-engineered approach.

27th May 2013, 19:31	#34
steve811 Banned Rover 75 Tourer CDT Connoisseur SE Join Date: Dec 2010 Location: Newport Posts: 1,906 Thanks: 107 Thanked 299 Times in 206 Posts	Sorry, that was not meant to appear belligerent!

27th May 2013, 22:16	#36
steve811 Banned Rover 75 Tourer CDT Connoisseur SE Join Date: Dec 2010 Location: Newport Posts: 1,906 Thanks: 107 Thanked 299 Times in 206 Posts	Thanks Steve, that confirms what I thought, the cone and the interrupted thread have no real significance now!

1st June 2013, 15:19	#38
steve811 Banned Rover 75 Tourer CDT Connoisseur SE Join Date: Dec 2010 Location: Newport Posts: 1,906 Thanks: 107 Thanked 299 Times in 206 Posts	Well, the bolts turned up on Tuesday and today I set about changing them. That's when I found out that the bolts do need to be flanged! The reason is that the high torque loading (100Nm) tends to bed in the head of the bolt into the relatively soft steel of the suspension bracket! I tried putting a washer underneath but that just dished under load, so I have ordered some really thick (5mm) thick washers to spread the point loading of the bolts. Until then the original bolts have gone back in!