Broken MX83 cradle

[andrew_mx83]

i very strongly doubt that will ever crack again. look at the size of that plate! the whole thing is one piece (including where the bush sits) and was machined from a 4kg chunk of billet. it is seam tig welded all the way around plus 4 big plug welds. i think there is about 3 hours just welding in that little plate.

its been in for about a year now. ill try and take some pics next time i am under there and i bet it will still be crack free

[PlacentaJuan]

i dont think he is saying that the double plate will crack, but that all the doubler does is move the weak point further out from the center (ie: to the edge of the double plate, which i tihnk is where he is saying it will crack next)

[andrew_mx83]

yes but the load is now spread over 2 or 3 times the area, plus there is not a big hole with an edge for the crack to start. the cicrle that the bush sits in originally is only tack welded on in a couple of places so once it breaks (mine was floating around the hole, loose) of course the vertical section is going to crack.

the main goal in designing that plate was to spread the load over the biggest area possible, if u have a look at the bottom it is also welded onto the horizontal part of the cradle so it has some strength against twisting and again spreads the load over more of the cradle so there is even less stress at any given point to allow a crack to start.

[petergoudie]

Yes, that's what I was saying. The load will be moved futher out around the 5mm plate (although we are talking about fatigue over a long time as even as standard they last about 10 years).

Remember, if you lie on your back and look up at that cradle/carrier it's pretty bloody light. It has about 10 or 12 mm turnovers to make it a c-section. In these forums some of the cars are developing a lot of power and even fitted with a standard engine that carrier is lightweight and bound to flex. As I said, I would be turning it into a box section (in reality a long thin rectangular shape) and turn up on a lathe a few longer flanged spacers for the mounting bolts and weld them to both sides of the box to strenghten up the whole lot.

[andrew_mx83]

yes, the load is moved out BUT SPREAD OVER MORE AREA.

that is the key. less load on any specific point which might be likely to crack.

[TIMTAMS]

i just picked up a parts cressy so i will doing pretty much what you have done andrew as i agree that would be sufficiant. i would really like to use a JX setup as i understand they run two front diff bolts as mine only has one...

[andrew_mx83]

ma70 diffs hasve 2 front boltsi think

plus better ratios

[TIMTAMS]

MA70 you say, i might do it it in the future. I want to do other things like sell the R154 setup and go auto...

[andrew_mx83]

there you go. u have to use the cressida rear cover still.

http://forums.toyotacressida.net/for...highlight=ma70
http://forums.toyotacressida.net/for...ight=ma70+diff

i think the 2 bolts at the front would help take a lot of up/down stress off the rear bolts.

[PlacentaJuan]

i dont like how much you have to cut out of the cradle though, seems like you are putting weak points back into it.

[TIMTAMS]

well half my problems were actually with the installation of the diff (not done by me).

I pulled it out to look at the extent of the damage and realised the diff was all crossed up and crooked.
Well the main reason for that was on the front bolt there is a sequence in which all the spacers and nuts etc. Well the spacer that has a locating rim on it was upside down which in turn lets the diff twist up to 30mm!!! So i pulled it all apart fixed it all up and i also found that one of the strut inserts was also stripped at the top which also gave me a knock!

So now its alot nicer to drive.... For now as i still need to fix the cradle

[1JZ.747]

if you go onto my website., lookup the magazine article which is also in my members rides thread, theres a photo of mine.

its a bit neater then the one posted on page 1. the other difference is mine has a larger bush and the sleeve has supports on it to add more strength., i still run this setup to this day and i have not had a problem, and i would suggest mine would have had more abuse then every modified mx83 on this forum put together.

pedders suspension at gateshead in newcastle can supply the bush same as mine there number is 0249421143.

if you tell them your problem and you want to copy whats done to mine you should be right

[TIMTAMS]

Hey thanks heaps dude thats awesome! Plus rep for you :-)

[PlacentaJuan]

someone post up the pedders part number when you get it.

save me having to deal with them any more than i have to

[1JZ.747]

someone post up the pedders part number when you get it.

save me having to deal with them any more than i have to

are you always so cranky?

my local pedders guys are awesome to deal with