Further Barke Problems

ZF, only close inspection of the cylinder and all it's internal parts will tell. My admittedly not unlimited experience of dual-circuit systems is that they can be more than twice the bother of single circuit to get right and that's just getting the air out!

Originally Posted by Wrenched

You're presumably not talking about a long run down a mountain pass?

No, just from a 60-70 mph run on A/B-roads around Lincolnshire. I wouldn't dare take it down a mountain pass with those brakes !!!

As I've said before, I'm really no expert on any of the mechanics of brakes - but I do know know that they just aren't right! The strange thing about the rear wheels and the heat is that there is absolutely no brake dust on the wheels at all. I wonder if this points to the handbrake, which still only has to clicks before it comes on enough to hold the car - which I think is a bit (!) tight. What do you reckon? I think the handbrake is a shoe and drum system inside the hub?

I've heard that the Spiders (at least some of them) have drum handbrakes inside the disc and my guess is that with your seemingly rather tight handbrake adjustment the shoes might be dragging causing the heating. What makes me doubt this is that the wear on the shoes with them dragging would be rapid and one might expect the issue to go away. If the handbrake is self-adjusting theat's another matter, or if work has been done on it lately then they handbrake might have been re-adjusted incorreclty. If enough heat is generated (you say you can't touch the back wheels after a run) then the brake fluid can overheat and give all sorts of irratic results at the pedal as it boils.
I'm sorry, I'm butting it without enough specific knowledge of the models; just like butting in I suppose!
PS you're sure all the flexible hoses in the system have been replaced with new (good) ones?

the handbrakes are not self adjusting, they are adjusted by turning a small brass gear which is visible through a small circular hole (two holes actually only one adjuster) in the outside face of the drum.
if you want to lay that one to rest, just jack up the car at the back, take the wheels off, back the adjusters off so the hub turns freely by hand, refit the wheels and test it out.
If the hubs are still too hot, it's not that.
You then need to look closely at the calipers and/or the rear axle bearings.

Originally Posted by Wrenched

I've heard that the Spiders (at least some of them) have drum handbrakes inside the disc and my guess is that with your seemingly rather tight handbrake adjustment the shoes might be dragging causing the heating. What makes me doubt this is that the wear on the shoes with them dragging would be rapid and one might expect the issue to go away. If the handbrake is self-adjusting theat's another matter, or if work has been done on it lately then they handbrake might have been re-adjusted incorreclty. If enough heat is generated (you say you can't touch the back wheels after a run) then the brake fluid can overheat and give all sorts of irratic results at the pedal as it boils.
I'm sorry, I'm butting it without enough specific knowledge of the models; just like butting in I suppose!
PS you're sure all the flexible hoses in the system have been replaced with new (good) ones?

Don't worry about 'butting' - it's good to hear some different opinions! Although we all seem to agree on most of the problems, which I think is good! As for the flexi hoses - definitely three new ones, coming from Alfaholics, although I possibly should have had braided ones fitted .

Originally Posted by VeloceMitch

the handbrakes are not self adjusting, they are adjusted by turning a small brass gear which is visible through a small circular hole (two holes actually only one adjuster) in the outside face of the drum.
if you want to lay that one to rest, just jack up the car at the back, take the wheels off, back the adjusters off so the hub turns freely by hand, refit the wheels and test it out.
If the hubs are still too hot, it's not that.
You then need to look closely at the calipers and/or the rear axle bearings.

I'll mention this to Tom/Phil at BLS tomorrow when I take the car in. I was promised by the guy that did the original work that the calipers were perfect. I have to admit that the handbrake does worry me, so I'll get them to adjust it I think. Also will get them to check the bearings - do they make any sort of noise when they're knackered? Only I do notice a slight scraping noise when the car is cold....?

I really appreciate all this help guys - even if it's just to be able to rule some bits out!!

The scraping noise is more likely brakes rubbing slightly, nothing to worry about. A bearing failure is a rumble that changes pitch when you turn loading and unloading the offending bearing.
A point to be aware of is that the 105 rear axle can have a lot of side to side float in it, which means the wheels can appear to move slightly in and out of the axle. This is a strange characteristic which often fools very competent mechanics into thinking the bearings are knackered. An early post suggest this float could also cause the calipers to tend to lock up which is interesting and might be affecting your braking, but I think it's a long shot to be honest.

Originally Posted by VeloceMitch

A point to be aware of is that the 105 rear axle can have a lot of side to side float in it, which means the wheels can appear to move slightly in and out of the axle. This is a strange characteristic which often fools very competent mechanics into thinking the bearings are knackered.

Do you mean the whole axle itself moves, or the hub & halfshaft in relation to the axle? I have a slight in-out movement on one hub but not the other - is that the bearing or something in the axle?

Not the whole axle, actually that does too if the bushes are worn, but i meant the half shafts. it sounds like its the effect you have noticed.
It's worse on the later ones those fitted to S4's are reputely the worst.
I think it's related to the bearings and it's possible to shim them but it doesn't always get rid of the problem entirely.

I'd be inclined to check the bore, to be sure. for ovality, with an internal mic. the type with a DTI attached, for a quick accurate assesment, if all else has failed.:

End float in the half shafts would lead to long brake pedals as the pads are pushed back into the calipers.
I tend to disagree that a scraping noise is nothing to worry about, it implies the brakes are dragging.

Originally Posted by Wrenched

End float in the half shafts would lead to long brake pedals as the pads are pushed back into the calipers.
I tend to disagree that a scraping noise is nothing to worry about, it implies the brakes are dragging.

Thanks for this - the car in in the garage for repair now. I'll forward the info on to them for a check.

Everybody keep their fingers crossed for good brakes and no hot wheels and no leaking pinion seal when I get it back!!!

Is there a 'fingers crossed' icon? Surely a place like this needs one!

Originally Posted by Wrenched

Is there a 'fingers crossed' icon? Surely a place like this needs one!

Definitely should be

here you go, hope this helps.

Originally Posted by Spider.S3

here you go, hope this helps.

Just the ticket!!

Sorry to those who've read this on AROC but to those who haven't....

Update - Just spoken to the guys at BLS. They can definitely see what I mean about the dodgy brakes. They have observed that in an emergency brake situation that the brakes really do their job, nose diving etc. But upon gradual/gentle braking the brakes are not so good, or in slow moving traffic etc. Also, the temperature difference in brakes shows that the rears get much warmer than the front. Could this be because the rear regulator that was replaced is on the wrong way around? It has two arrows at right angles to each other - anyone know which way they should point?? At mo, one is pointing down to the floor, the other in the brake line direction.

It seems that we are going to try new servos...