alcazar

iTrader: (2)

Started to replace discs, pads and brake shoes today. Luckily Andy (Chocolate O'Brien) was here, I don't think I would have got them out at all.
TWO bolts, one on each caliper, had seized solid and stripped the threads out of the caliper body.

What a STUPID design!

Both calipers now on the way to Godspeed for helicoils.

FOUR new bolts needed.

I wouldn't care, but I used brand new bolts to fit them, and put loads of Copper Eze on them

And now, once they are refitted, I have to bleed the whole lot.
NOT a good day.

B0DSKI

iTrader: (17)

Seems to happen everytime with Brembo's mine did exactly the same on my old STi

mantazini

iTrader: (25)

Had this as well. Easy fix thought. Got a kit from ebay and done it myself. Their aluminium thats the problem

53

iTrader: (41)

Tis a ****

I always lube with plus gas the day before and they crack no problem

It is stupid though

ditchmyster

iTrader: (7)

+1 on the lube.

alcazar

iTrader: (2)

They were lubed, and had been plastered with copper grease before fitting, but STILL seized up.

Can calipers be fitted with decent STAINLESS bolts? Would that help?

daz1968

iTrader: (13)

It's the aluminium that corrodes not the bolt, best way to protect is to isolate steel from the stainless and keep water out, copper grease is only thing I can think of, unless there is a soft thread sealer that can be put on the bolt

rob84

iTrader: (5)

you can use an alloy slip as the copper stuff goes hard with heat and time

alcazar

iTrader: (2)

Stainless bolts no good then?

T5NYW

iTrader: (4)

No dont use a general stainless bolt as they are far too "soft" iirc "A2" you can get "A4" which is a higher tensile strength IIRC imho

But using helicoils and good quality hi tensile bolts shouldn't be an issue

But as said the main issue is the alloy corrosion and extreme heat. So agree with DAZ

.

Tony

tubbytommy

iTrader: (20)

mine did that too so i chucked em away....

SLAB

iTrader: (77)

what about titanium bolts

ALi-B

iTrader: (1)

Copperslip is only good for a couple of years, depending on how much use the car gets on Britain's over-salted roads. (I must be the only person who wants road gritters to be banned )

One problem with copper slip is the threads tend to wipe the copper slip off when they are inserted unless you put the copper slip into the thread NOT the bolt (well, you can do both ). Even then the protruding piece of bolt thread sticks out...Which you can't see as it faces the disk and rusts up. This rusty piece then has to be dragged through the caliper thread when undoing it...which cause the bolt to shear or wreck the thread. So before undoing it you need to get at that bit of bolt that's hiding behind the disk with some good quality rust penetrant like Wurth Rost off plus with a straw attachment (not WD40- that just a low viscosity oil, mediocre at best). But any lube of that exposed bolt thread is better than no lube....just spraying the bolt heads will do eff all.

And yes you should make sure the replacement bolts you use are of the correct grade steel...FFS don't use random stuff bought from B&Q etc. Even some bolts supplied in some kits are rather dubious IMHO (FWIW I've had the same issue with the quality of bolts supplied in aftermarket ball joint kits).

T5NYW

iTrader: (4)

110% agree and top tip



Tony

speedking

I am just about to do this job and having read this thread I've read quite a few more on t'internet. Wish I hadn't seen it Couple of questions:

1. I suppose there is a chance of the bolts just coming out? I changed the discs on my bugeye WRX with no issues. Does anyone in the know know what % are likely to have a problem. At 6 years old is it close to 100%, in which case I seriously need a Plan B if the car is on the drive with stripped calipers!

2. Might it be better to attack the bolts with an air wrench. A shock load might break the seal making it more likely that the bolt will come out cleanly, whereas using hand tools the build up of force is slower maybe causing more issues?

I don't have a second car to use so maybe I should go to a garage and pay a massive premium as the cost of taxis etc. may work out to be more expensive. As this month has seen service, 4 x tyres, windscreen excess, brakes and new diff temp sensor, I'd like to keep the costs down if possible.

Any thoughts?

Turbotits

iTrader: (2)

Ive had mine off 3 or 4 times in the 10 years ive owned the car without problem.

I tend not to pull on a bar to crack the bolts. I put a socket on with an old T bar and give the T bar a good couple of spanks in the right direction with a hammer... Whether the shock to crack the bolts works or I've just been lucky i cant say,But it works for me.

Henrik

iTrader: (5)

I think the stainless bolts might be making it worse, as it's more noble than e.g. mild steel bolts, which means that you'll get faster galvanic corrosion going on between the aluminium caliper and the bolt.

Has anyone tried using mild steel bolts?


Galvanic corrosion info here: http://en.wikipedia.org/wiki/Galvanic_corrosion

Godspeed Brakes

iTrader: (259)

Yes Subaru did , mild steel bolts were fitted at the factory

Henrik

iTrader: (5)

ah, and they're ****e as well I take it?

Godspeed Brakes

iTrader: (259)

Its not the bolts fault , its the fact they are threaded straight into alloy , Brembo should be putting steel inserts into the calipers as this would stop the problem , but I guess that all comes down to cost.

IggyRB320

iTrader: (9)

I changed the RB320's last year & they come out ok.
Although, on speaking the the guy who used to do the PDI at the dealership I bought the RB from, they used to remove the bolts when new (as part of the PDI) copper slip & re-fit!

alcazar

iTrader: (2)

That's how mine were fitted, but to no avail.

Henrik: stainless aren't used as standard, probably since they don't have the tensile strength.
But the stainless doesn't react, so would be LESS likely to corrode.

Henrik

iTrader: (5)

It's not the stainless that corrodes, it's the aluminium.

toneh

iTrader: (1)

Might sound the wrong thing to do but , a drop of thread lock might help long term because it will help stopping water ect fully penetrating the threads which is the cause of the corrosion
Just don't choose one that is super strength that requires heat for removal
Loctite do a vast range from virtually non set to super strong

dunx

iTrader: (3)

It's the exposed thread that is the problem, shorter bolts would help.... ideally into a blind hole, not a through hole exposed to the elements.

IMHO.

dunx

toneh

iTrader: (1)

Doesn't matter if the hole is exposed or not really , or the threads that are sticking through , it's galvanic corrosion between the two metals that's the problem , the sacrificial metal being the aluminium alloy of the caliper the only way to help stop this is by forming a barrier between the two metals with as suggested , grease or loctite

Henrik

iTrader: (5)

Grease might act as an electrolyte (possibly). I like the weak loctite idea, as it would set and a bit of heat would soften it enough for the bolt to be undone easily

toneh

iTrader: (1)

Some don't require heat for disassembly mate ,loctite 243
Doesn't , it can be undone without the need for heat or loads of torque
And will help stop to an extent water ingress , of course not 100% seal or barrier but every little helps

alcazar

iTrader: (2)

Loctite sounds a good idea. Grease, well I tried that, I daren't have put any more on, and it didn't work.

A better idea would be for Brembo to use stainless inserts from the off. They could cast the alloy round them, or fit helicoils.

It's obviously a problem and left to the end user to fix, while Brembo continue to be lauded as brilliant and sell for £££'s.

They don't even use stainless bleed nipples. Even my Hope mountain bike brakes have THOSE!

speedking

Started the job this morning. First bolt came out with aluminium clogging the threads Off to the helicoilers we go