Looks like i lost a magnet on Sunday. Speedo suddenly started reading half after a spiritted section. Only done 1100 miles in the car.

I secured them with plenty of araldite (and not the fast set stuff). Prop adaptor on diff was very very clean, rubbed down till metal was bright (not polished). Has anyone had a more long term experience? Can they be bonded with ematal?

Thanks for your help,
Darren.

[Edited on 25/9/06 by DarrenW]

Yep, araldite and then duct tape round the lot - worked for me.

You could try solder ???

Pat...

quote:

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Originally posted by Avoneer
Yep, araldite and then duct tape round the lot - worked for me.

You could try solder ???

Pat...

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I didnt think about duct tape - nice idea.

Im wondering if the gearbox oil that has liberally coated the inside of my transmission tunnel may have caused part of the problem. Ill take a better look tonight. I have seen the sensor plug is well covered!

As an interim measure, and I know it's not ideal, but couldn't you just double the 'pulses per mile' to bring it back in line?

I'm using the areldite method too, so would be interested in the long term reliability.

Cheers
James

This thread is getting added to my favs

Still got this pain to go through - have the Smiths Telemetrix dials and hope mine will be ok.

I'm off to buy some araldite and duct tape

That's funny I think I lost one on Saturday also, good idea about the duct tape!
Where can you get new magnets from?
Coz everywhere I go seems to be at 20mph or 50mph

Cheers

Rick

magnets buy em from maplin various types though.

Regards agriv8

I can get replacement magnets from ETB no problem.

Has anyone ever used JB weld to fix them in place?

I've got about 8 spare small magnets left.

Pat...

this is the most unreliable part of my car, i got bored of reattaching magnets so am using one, it seemed that on is still on from the original aralditing, the other won't stick foro longer thanthe first blat, sometimes you can feel it hit the tunnel!

Be careful with duck tape, i wound mine on the "wrong" way and it unwound and ripped the sensor from the chassis :-(

keep a mental note of rpm in top gear for speed cameras!!

Chas

Kinda following on from the magnet sensors has anyone fitted one of these

And was it a PITA - I mean other than the magnets falling off every five minutes!

I was thinking about one of those but decided to fit real one in the end.

had a look at the prop daptor today - one magnet has come out cleanly and left a perfect magnet sized hole in the araldite - so it didnt glue it at all. The second has evidence of the araldite coming away. And this was after speding ages cleaning and roughing the steel up.

I think i will JB weld them on this time.


Ref the duct tape - thanks for the reminder on direction.

Ive just got back from my mates garage. He has lent me a Wuth superglue kit. ive heard amazing results with it. I will be bonding them prinipally with this and adding the JB weld for extra security.

The only other solution i can think of is to drill a shallow hole to sit them in and bond them to the hole.

Hmm....in the 3 years I've had my car on the road, the longest a magnet has stayed on is 1000 miles.

So far I've tried:
jbweld
araldite
chemical metal

None have worked spectacularly well.

Might try the duct tape trick, but sorely tempted to relocate my sended to a front hub so the forces are working for me rather than against.

For those with an IRS car, I think the disc that goes between prop and diff is probably the ideal solution.

http://www.maplin.co.uk/Module.aspx?ModuleNo=26348&criter ia=magnet&doy=30m6

Well, i thought id post an update. To save you trawling my last solution was to clean to bright metal, wurth industrial superglue (2 part stuff with the spray activator) to initially bond them followed by JB weld all round and thin layer over the top.

Lasted approx 1500 miles before one fell off on Motorway at very tame speeds last weekend!

Once again i found the detached magnet stuck to chassis. 2nd one was very easily pursauded to come off with stanley knife. This time i have once again cleaned to bright steel (prop), scratched the surface up this time and used sikaflex. Good blob on the steel - magnet pressed into it. Liberal amounts all round and smear over the top. My reasoning this time is that the sikaflex is more compliant than other adhesives and should take the road vibrations much better.


Isnt it amazing that some people dont get any grief at all with araldite but others have to try all sorts of stuff.

Ill report back if they come off again.

I use a different kind of sensor these days - no magnet required.

However, previously I used to use "bead magnets", basically a magnet with a hole through it. Simply drill and tap what you want to fit the magnet too and screw it in place. A bit of locktite on the thread of the screw and its a permanent feature.

Try ebay for various shaped magnets.

If you are using a Sierra or similar IRS ETB do a disk which sandwiches between the prop and diff and the sensor works on that. Unfortunately I don't think it will work with a live axle as that will move within the chassis. Another possibility, although maybe expensive, is that the Granada type 9 box uses a signal generator for an electronic speedo, unfortunately I don't think they will fit straight into a normal type 9 so you will need a Granny box.

Try fitting the magnets to the drive shaft , the turn a lot slower than the prop. Alternatively try using the diff flange bolts instead of magnets thats how I ended up doing mine . If you do it that way try to make sure that all the bolt heads are in the same position relative to the flange . Had no problems at all with mine.

quote:

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Originally posted by Schrodinger
If you are using a Sierra or similar IRS ETB do a disk which sandwiches between the prop and diff and the sensor works on that. Unfortunately I don't think it will work with a live axle as that will move within the chassis.

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because the distance between the bolts is the same!

Sow in theorie should have a dancing speedo!

Tks

I fitted my magnets to the output flange of the diff.
I drilled a hole the same diameter as the magnets and about 4mm deep.

Blob of araldite in the hole, pop the magnet in and another blob on top.

Seems to have held in so far!

Cheers,
James

Interesting you should say that James. I have spoken to John at ETB (top bloke), he suggested drilling the hole etc is a good way to affix problematic magnets. he also sent me a spare set up as well which was really good of him.
He also recommended Loctite 326 with activator 7649 as an excellent adhesive to use (he said only way to remove afterwards is with hammer and chisel!) but at £20 for 50ml bottle and £7 for activator it aint cheap.

Looks like araldite (and plenty of it) and shallow hole is the most robust locost solution.

Hi,

ETB do a bolt head sensor for the DD2. It's a bit more expensive but it uses the same plug and can pick up of 4 bolt heads....

Maybe give that a go if you cannot keep the magnets on.

Al.

chemical metal and gaffa tape seems to be a winner for me....