sub frame / radius arm

sub frame / radius arm

Author
Discussion

huwbertus

Original Poster:

59 posts

248 months

Friday 18th February 2005
quotequote all
Decided to get my Marcos rolling again only to be left scratching my head.

It appears that
a) My new subframe is out of alignment
b) My reconditioned radius arm is faulty

when mounting the radius arm in the subframe all goes well right up untill the four bolts that hold the outer pivot support plate need to be insterted. The problem seems to be that the radius arm pivot shaft is too long as the bolt holes are about 4mm out of alignment.

If you understand me I would appreciate some ideas

Cheers Huw

Cooperman

4,428 posts

257 months

Friday 18th February 2005
quotequote all
Just a thought, but have you missed out one of the large spacer washers which sit on each end of he pivot shaft and around which rubber ring sits? They are about 4 mm thick and their omission could cause this. If not, then I am baffled.

Peter

cone

471 posts

242 months

Friday 18th February 2005
quotequote all
after market frames, dont always fit ! build it back up without arm in nd measure the width nd then measure old one nd width of radius arm/2washers and shaft, you should then find wots up .

huwbertus

Original Poster:

59 posts

248 months

Friday 18th February 2005
quotequote all
With the big washers I am assuming that there should be one at each end of the radius arm pivot and it is this that is effectivley making the radius arm pivot to long, pushing the mounting bracket out to a point where it can not be bolted on.

cone

471 posts

242 months

Friday 18th February 2005
quotequote all
take the shaft out of the arm , put the washers on the shaft then try to fit shaft nd measure up . have u got an old shaft to compare it wid .

huwbertus

Original Poster:

59 posts

248 months

Friday 18th February 2005
quotequote all
If I get a chance I'll have a look tonight.

Any idea how long the shaft should be between mating faces? And how big the gap in the subframe should be?

To me it looks like the shaft is sitting a little proud one side of the radius arm. Should the mating faces (Where the tread ends) be flush with the outer edge of the arm?

Cooperman

4,428 posts

257 months

Friday 18th February 2005
quotequote all
With the big washers on each end of the shaft, the shoulders on the shaft, where the threaded portion starts, should be just slightly proud of the washer faces to ensure that the shaft is 'nipped' between the subframe face and the subframe bracket face.
I've never had this problem and can't think what it could be.
The width across the arm from the faces of the washers when fitted should be 2x one washer thickness plus the dimension across the radius arm faces against which the washers fit. This should be just a few thou less than the plain length of the pin from shoulder to shoulder. I've never actually measured this.
It doesn't sound like a sub-frame problem though as although the holes are not always accurate, they are normally fairly close. Unless, perhaps, you are using different end fittings from those supplied with the frame. This is not normally a problem, but who knows with BMC/Rover tolerances.
I hope this helps.

Peter

cone

471 posts

242 months

Friday 18th February 2005
quotequote all
212mm of shaft, yup it shou be flush with radius arm.

cone

471 posts

242 months

Friday 18th February 2005
quotequote all
Cooperman said:
With the big washers on each end of the shaft, the shoulders on the shaft, where the threaded portion starts, should be just slightly proud of the washer faces to ensure that the shaft is 'nipped' between the subframe face and the subframe bracket face.
I've never had this problem and can't think what it could be.
The width across the arm from the faces of the washers when fitted should be 2x one washer thickness plus the dimension across the radius arm faces against which the washers fit. This should be just a few thou less than the plain length of the pin from shoulder to shoulder. I've never actually measured this.
It doesn't sound like a sub-frame problem though as although the holes are not always accurate, they are normally fairly close. Unless, perhaps, you are using different end fittings from those supplied with the frame. This is not normally a problem, but who knows with BMC/Rover tolerances.
I hope this helps.
just what i was tryin to say pete but it would take me ages wi one finger, nd yes give or take n inch to allow for rover !

Peter

cone

471 posts

242 months

Friday 18th February 2005
quotequote all
as you can tell i haven t figured out how to quote other people yet soz pete .

guru_1071

2,768 posts

241 months

Friday 18th February 2005
quotequote all
cone said:
as you can tell i haven t figured out how to quote other people yet soz pete .


cone.

its your age.....

i'd give it up if i where you, sell your mini and buy some slippers and a montego..


:-)
:-)

cone

471 posts

242 months

Friday 18th February 2005
quotequote all
ah ur back , hows jims rash .ha ha

w00dy

919 posts

244 months

Saturday 19th February 2005
quotequote all
fitted a non O/E subframe a few years ago, and as it turned out one of the outer location brackets had been made incorrectly with the hole being about 3mm out of place - meaning that the arm woldn't fit. Welded the hole up, ground it down and had it re-drilled in the correct place. Lesson learned, always O/E or better from then on.

guru_1071

2,768 posts

241 months

Saturday 19th February 2005
quotequote all
hugh-bert-us

need more info...

1) is the frame pattern or genuine???
2) is the radius arm a exchange unit???
3) is the pin kit one you fitted to the arm yourself - if so is it pattern or genuine???

also where did you get the bits from??????

answer these and i'll polish my crystal answer ball!

huwbertus

Original Poster:

59 posts

248 months

Sunday 20th February 2005
quotequote all
Ok then Guru here you go

1 It is a pattern frame
2,3 Yes. The arm is a reconditioned exchange unit

Bought from my local parts suppliers months ago (Partco and CES) as the price was about the same as most mail order outlets without the postage costs!

WildfireS3

9,832 posts

259 months

Sunday 20th February 2005
quotequote all
I had a similar problem a few years back when I bought a brand new SF from Mini Spares. Turned out it was a faulty batch of SFs. Tried 5 different ones, same problem from 3 different shops, same problem as they all source from the same manufacturer.

guru_1071

2,768 posts

241 months

Sunday 20th February 2005
quotequote all
i doubt the frame is faulty as most pattern ones seem to come from the same place nowadays. the only problems with them are that the handbrake guide quadrent is often welded on in the wrong place (to far forwards) and that occasionally the pin mount holes for the radius arms seem to be inaccurate (im convinced this is a incorrect rumour and is more often one of the following problems.....)

the cheap pin kits that are avalible now are often slighty too long (compared to gen rover) this allows the arm to float side to side even when every thing is tightened up.

the other problem is with recon arms, the core that is avalible is so worn now, that the reconditioners are milling the ends out and pressing little top hat shaped bushes in to remake the surfaces where the bush and bearing fit. lazy practices and no checking allows arms that are longer and shorter than standard to be common. this of course linked with the pin problem is a recipe for disaster. ive seen arms with up to 5mm of side to side float on them!!

of course much of the problem is with customers demanding recon kits for a tenner and recon arms for 30 quid isnt helping with any quality control issues!!

i have resorted to using the kits, but checking the pins for length and machining them if required, then reconning my own arms and reaming them myself, sure it takes a long time but i know they are right!

the other problem with recon arms is knowing if they are bent or not, ive just had to swop a arm on a mates car that had a very 'hello sailor' look to one of the back wheels!!!

ive also found that the pin kits for the front top arms are also often to long!!!!

arrrgggg!!!!!

its the old saying, pay cheap, pay twice!!!!

WildfireS3

9,832 posts

259 months

Thursday 24th February 2005
quotequote all
guru_1071 said:
i doubt the frame is faulty as most pattern ones seem to come from the same place nowadays. the only problems with them are that the handbrake guide quadrent is often welded on in the wrong place (to far forwards) and that occasionally the pin mount holes for the radius arms seem to be inaccurate (im convinced this is a incorrect rumour and is more often one of the following problems.....)



Nope it was definitely the SF, the retailers actually admitted it and had to send the whole batch of SFs back to the manufacturer. They managed to find one from a previous batch with different batch number and low and behold both arms fitted no problem. Also this was using genuine Rover Parts.

This was around 3 years ago, mind. Chack by seeing if the same arm ifts upside down on the other side, if it's off the car.

But in this case it may not be a faulty SF, but go down to the supplier with the SF and ask them to check it out using a spare radius arm.

huwbertus

Original Poster:

59 posts

248 months

Monday 28th February 2005
quotequote all
Tried the bearing rod from the other side in my re-con arm and it fits OK ish!!!!!! So I will be getting the bearing rod turned down a couple of mm.

One bolt hole was still out of alignment though on the subframe.

Cheers for all the help
Later
Huw

huwbertus

Original Poster:

59 posts

248 months

Wednesday 9th March 2005
quotequote all
Sorted. Bought a radius arm rebuild kit instead of turnig the original one down and it fits like a glove.

I eould advise that when buying a reconditioned radius arm to do up the nuts each end complete with washers (leave the rubber seals off) to make sure that the arm bearing is not to long. there should be hardly any movement along the axis of the bearing.

If I had done this it would have saved me £15.

Cheers for all the support
Huw