Diff problems?

[Ceylon]

Nice, saves some dosh at least. I've had a look but can only see find home made ones or mazdaspeed.. care to name some brands?

In terms of the alignment etc can I just whack it off and back in on the street with a jack and stands or will I need a ramp for it.

And I thought I was just needing a front mount doh!

Yeah, it's just rolled steel, nothing special to weld really, just don't put silly heat into it and warp it and you'll be fine . Of if you've got a spare diff, bolt it up when you weld it, that would be ideal.

Alignment wise, you'll be fine on axle stands, that's the way I've always done it! If you tighten it in the top-down order, rear first then do the measurement, I've always had them be in spec so far.

I'd much rather pull a PPF than a diff, cheaper too .

 

[JonFD]

Yeah, it's just rolled steel, nothing special to weld really, just don't put silly heat into it and warp it and you'll be fine . Of if you've got a spare diff, bolt it up when you weld it, that would be ideal.

Alignment wise, you'll be fine on axle stands, that's the way I've always done it! If you tighten it in the top-down order, rear first then do the measurement, I've always had them be in spec so far.

I'd much rather pull a PPF than a diff, cheaper too .

Coolio, what are these measurements lol?? Are they in fsm?

 

[Ceylon]

Just one measurement between the PPF and tunnel brace, it's in the FSM, yeah .

That and the obvious one by eye, is the gear stick central in the tunnel hole.

 

[JonFD]

Just one measurement between the PPF and tunnel brace, it's in the FSM, yeah .

That and the obvious one by eye, is the gear stick central in the tunnel hole.

Nice one, I'll update with some pics after mines done, hopefully it was just this.

 

[Paulm]

Thanks Tom for your advice, I've had a read up and it seems that i will have to do a few things to get the ppf repaired and protect it from future failure.
Engine mounts - check and replace
Diff mounts - replace
Ppf - weld crack and reinforce ears and a few other areas

From what I've read the ppf needs to flex a bit to reduce torsional load on the diff. Otherwise i risk the diff casing cracking.

Does this seem correct?

 

[JonFD]

Thanks Tom for your advice, I've had a read up and it seems that i will have to do a few things to get the ppf repaired and protect it from future failure.
Engine mounts - check and replace
Diff mounts - replace
Ppf - weld crack and reinforce ears and a few other areas

From what I've read the ppf needs to flex a bit to reduce torsional load on the diff. Otherwise i risk the diff casing cracking.

Does this seem correct?

Been wondering about how much to do myself, I'm thinking to do the area that broke and the bits around the mountings, they seem weakest, but theres plenty of pictures of them in half too so wondering about plating the whole length ?

I read that about the flexing, was it in the thread the guy welded a load of triangular plates down it? His looked pretty good too..


I'm going to get some plates on monday, can anyone recommend thickness of steel I should get?

 

[Paulm]

The americans were using 1/8" steel, so i would go with 3mm

 

[Paulm]

I've decided to weld up the crack and add a small amount of reinforcing plates around the problem area, similar to this picture, shamelessly borrowed from rx7club, the pink and blue bits are new steel. I have decided against adding stiffening plates along the whole ppf, it seems to me that the ppf is designed to flex, and the only reason that for that would be to reduce torsional loads on the diff casing.

 

[JonFD]

The americans were using 1/8" steel, so i would go with 3mm

Cheers mate.

I think we're planning the same thing then, I found that pic but its so small its hard to see whats going on with it.

Also do wee need to worry about clearance if we add material to the top or sides ?

 

[JonFD]

Well mines with the blacksmith for the welding and strengthening. I really did want to do it but decided against it as I've only welded like twice and no welder.

Was a bit of a jiggle to get it off, may have to drop the zorst to get it back on which will be fun on my own lol - also I can't get the car completly on stands as the road is too angled.

Pics tomorrow.


- side question are the cheap ebay/amazon migs any good they only have 4 voltage settings on a switch...

 

[Nas80]

Well mines with the blacksmith for the welding and strengthening. I really did want to do it but decided against it as I've only welded like twice and no welder.

Was a bit of a jiggle to get it off, may have to drop the zorst to get it back on which will be fun on my own lol - also I can't get the car completly on stands as the road is too angled.

Pics tomorrow.


- side question are the cheap ebay/amazon migs any good they only have 4 voltage settings on a switch...

I got a Clarke 90 it's never let me down when. I have had to cut out rust and weld in a new bit. .

You need something that can weld 5mm so none of the cheap ones will do it in suspect.

Just take it round to an exhaust place and they word probably fix it for a tenner.

 

[JonFD]

So I picked up ppf last night, have a look at this badboy ..

The guy did more than I asked him too, when we marked it up he carried on and did a whole load more I didn't even think about.
I like way he did the brace between the gearbox mounts, looks good, almost like the RE Amemiya one. He just did it of me describing it too - hope it clears everything..

.

.

 

[Paulm]

Looks like hes done a good job, let us know how it fits

 

[JonFD]

Ill update shortly...

I'm worried about this bit, but after looking at gearboxes for the last 20 mins I think I'll be fine - rather get the grinder on it now than after swearing under the car lol

 

[JonFD]

Success !!!! lol.

It fits up fine, no issues at all. no pics as my phone died and I really couldn't be asked to wait.

I can't believe how many problems the ppf can create, I've been getting an occasional crunch into reverse, and sometimes a bit of a notchy 2nd, even after a gbox rebuild (got stuck in 5th- fun times) All of that's gone - I've adjusted the clutch pedal rod about 3 times now trying to solve that previously..

I didn't get that gear type noise either the one I started the thread over but I couldn't really test with much boost as traffic etc. Did get the rear wheels to spin up a bit, and I got zero wheel hop, so such a win so far.

Also I found a nice 2x 2p sized hole in the top of the back box, and took that to get patched, made me finish late and in the dark but now the cars quieter too, more winnings lol.

 

[Paulm]

Did you cut that extra brace out?

 

[JonFD]

Did you cut that extra brace out?

None of it at all, it all fitted up perfectly, there is a fair amount of space where the lower part of the gearbox mounts to the ppf so you'll be good doing anything similar

 

[JonFD]

Hi guys,

The noise is still there... Its a fast hard clunk/hard tapping - only thing I can liken it to is a bad cv on full lock on a front wheel drive. The sound is almost 100% from the middle of the rear sound like the right centre to me and left centre to passingers.

It's no way as bad as before - it's now intermittent, only under heavy load, as in a decent launch or a hard shift into second. It does not seem related to any wheel hop, and in the damp its not apparent at all. It won't last the whole way through a gear either, just under the initial 'dip' from the rear.

I can make it happen by holding the hand brake at lower speeds while accelerating into the load (not good or clever i know but harder to tell at full throttle plus noise etc) - kinda proving the dipping under load thing

Could it be an inner CV? it's the only thing it sounds like, I cant see or feel anything else out or broken after the PPF, the diff doesn't have any excess play in it's mounts (tried with a prybar etc) There doesn't seem to be ant excess play in them or the diff.

Could it be the diff? I do get light whine all the time but it locks up fine and the noise is only intermittent. - Diff does clunk abit of you turn the drive/prop shaft hard by hand?

Running out of ideas here lol

 

[jdmr_neil]

It's not suspension related is it, evident only what the car squats down on the rear?

Broken spring or something.

 

[JonFD]

Yup deffo when it squats - and no got a spare meister as one of my ohlins is off for service and thats all good,

Suppose I should be asking what was I hearing (same as now but worse) when the PPF broke?

I'm assuming the diff got tilted under power, but which way? I'm thinking the inner cv got put at an extreme angle and with power gave way?