What would anybody recommend?

[Bob]

Hi all, I've just returned from the MOT centre to be told that a rear brake disc is warped. I've wondered if the original set up of front 132 brakes and rear Betas is worthy or if I shouldn't go a bit bigger (vented etc). I must admit braking has never seemed a problem even with this set up but I wondered wether to skim the disc and stick with what I've got or change now. Having said all that it would need to be within the realms of my meagre budget!.

Thanks in advance for any advice, greatly received.

Cheers

Bob.

[x19er]

Bob,

I think you have answered your own question:

"I must admit braking has never seemed a problem even with this set...it would need to be within the realms of my meagre budget"

John ;)

[chris.richard]

Bob, I think I've a set of hardly-used discs....

[Bob]

Hi Chris, thanks for your reply, I've sent you a pm.

Bob.

[CorseChris]

Worth a read.... http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

[Bob]

Hi Chris, as you said it's an intresting read. I was surprised when I was told it was "warped", the chap who drove it to the Mot centre said he couldn't feel any brake judder at all, neither can I. You can see where the pad misses on the disc though. I didn't get to bed in the disc/pads so I dont know if there was an issue there but the discs do look brand new. It might be worth me cleaning up the discs and fitting some new pads, I'll have to be quick though as if this would be a cure the current Mot runs out in a few days time!. Anybody know where you can get semi-metallic pads for Beta!. Can I prove my lack of mechanical know how by asking what's Garnet paper?!.

Cheers

Bob.

[Bob]

Got some new pads to fit and try bedding in, £10 for a set of semi-metallic pads from a local shop!. Think I'll give this a go, incase the disc is fine, if not new discs to get through the test and then maybe upgrade next year-anybody want to let me in on a preferred set up?.

Bob.

[CorseChris]

Bob,

If I read it right, that article would suggest that new pads won't help as the problem is with the structure of the disc itself. But at £10, well worth a punt.

FWIW, I have Wilwood 4 pot calipers at the front with Thema turbo 8V vented discs, standard Beta rear calipers with Tarox discs. Locks the wheels (which is all you can ever do) and for road use, I've not experienced fade, even blatting down the road from Llanberis to Beddgellert, so good enough for me. I might reconsider this once the V6 is fitted though :)

[shaun]

Any chance that the disk is not seated correctly on the hub, I gues that once the wheel nuts are tighten this would be avoided. Just a wild guess.

[Bob]

Worth a look, until I get some time at the weekend to have a proper look I'll have to keep listening to the advice you chaps keep proposing!.

Thanks for your advise,

Bob.

P.s. Chris, I have a V6 in mine, hence the idea worming away in the back of my head that maybe the standard set up is marginal!. Thanks again for your help.

[strat6v]

If i remember right, Phil bishops car had a standard brake set up with a v6. On his trip to italy, when driving over the stelvio pass his brakes caught fire :eek: . I think the wilwood clad owners didn't have any problems. Guy mayers would be able to clarify. I would certainly upgrade if running a v6.

A full set of 164 brakes would be the most cost effective upgrade but how much better they would work i cannot answer.

John.

[Bob]

I guess that would mean changing to 5 stud hubs/wheels ......etc?. I had a useful conversation with Chris R last night who said he thought Roger Donnan was racing with 4 stud hubs with what he thinks are Intergrale discs and Alfa 164 calipers. I guess if this works for racing it's probably the cheapest upgrade and it would be a matter of mounting the caliper some way. Is this right Roger?!.

Bob.

[CorseChris]

The 8V Thema turbo and Integrale discs are the same I think. Cheap and easily available 4 stud option. Fitting the Wilwood caliper to the Fiat 132 upright wasn't that hard, just needed someone with a milling machine! I did the drawings myself for a bracket based on Wilwoods own mounting blanks, but there is a nice drawing done by Jeff D in the archive that would work just as well if not better than mine.

To be honest, I'm not sure the rear Beta caliper is going to be a big problem for road use. Neil Simons used them in his twin turbo car for a long time before upgrading and I reckon he was making more power than most of us will see from a V6. Gary Lomas was using Beta rears on his old car and IIRC, he commented that although there was a good case for more braking effort on the rear of a mid-engine car, he'd not really found them to be a limiting factor in his rallying exploits.

Probably the best case for upgrading the rears would be spares availability I reckon.

The other factor to consider of course is how you are going to resolve the F/R balance issue if you aren't using a bias adjustable pedal box.

...but I bet Roger has the answer to all these questions.

[Bob]

There is an adjustable brake bias valve on my car and I've never altered it since I bought the car. It all seems to work properly and I had a chat with Steve at Alternative Autos about sourcing bigger discs. He reckons that the offending disc on my car is unlikely to be warped and that cars that aren't used that often and are left standing (usually after a wash!) can get a build up of pad substance on the disc and apparently doesn't get warn off with the next drive but actually gets glaced and if I clean the disc up, with new pads could quite easily cure the reading on the mot print out. I can give it a go at the weekend and see if it works.

Bob.

[chris.richard]

The other factor to consider of course is how you are going to resolve the F/R balance issue if you aren't using a bias adjustable pedal box.

...but I bet Roger has the answer to all these questions.

Roger uses the standard Fiat M/C - I don't know how, I couldn't seem to get it right, but he does.

[chris.richard]

There is an adjustable brake bias valve on my car and I've never altered it since I bought the car.


IIRC, these valves just delay the onset of maximum pressure to the rear brakes to avoid them locking first, without altering the balance of effort between the two circuits.

[strat6v]

Flow adjuster kind of?

[Sando]

The 8V Thema turbo and Integrale discs are the same I think.

...but I bet Roger has the answer to all these questions.

Hiya
Not sure about the rears, but I think the Thema Front Vents are only about 260mm and the Integrale's are 285x24mm and can be 4 or 5 stud depending on which model.
It's the offset that is the tricky bit using either of these discs, however if you are changing calipers at the same time then you'll need to remake the mounts to suit anyway. The big Brembo 4 pots off an evo will do nicely on the front too, but depends on your wheel offset to get them under. (guess how I found that one out ;) )

I'm going down the road of 4 stud Integrale vents all round (same as JR and JB, and a few others I think) but in usual can't afford it Sando fashion :( I'll be marrying up some 4x4 Cosworth Calipers all round, that I've got to hand.

I agree with you Bob about once they are locked thats it, but from high speeds having the extra torque of a bigger disc helps improve braking and by not having to work them so hard heat should also not be so much of an issue. keeping the servo or altering the leverage will have to be tried later to get the best feel, thats what it's all about IMHO :) .
Slicks make a massive difference too, so I want mine to work well on sprints as well as being useable on the road.

When I spoke to Roger about brakes some time ago, he had the line pressure adjuster in the front circuit so that he could back it off in the wet, but since then I think he said here on the forum he's had problems with the back locking up since he'd changed to 164 rear calipers.....Roger?

cheers
Rob

[rutthenut]

Front discs - yes, be aware of differences between 8v and 16v Integrale, and different Thema Turbo models, there are different diameters. And, it seems, different offsets. Depending which way the offset goes, a small shim-type spacer can work on the inside of the disc bell (think the Beta had this fitted as standard).

I've got Integrale front discs (not sure which ones now) and Princess 4-pot calipers. The rear has the Wilwood discs and 4-pot calipers, with alloy bells. Twin master cylinders on balance bar setup, slightly increased leverage on the brake pedal linkage too.

I used to have twin master cylinders, 1:1 ratio in linkage bar, and Thema Turbo discs and calipers front and rear. They stopped fine, but pedal effort was extreme - very hard to get to lock-up point with that combination. I would recommend using the standard duplex master cylinder if using single-pot sliding calipers.

The in-line brake limiting valve does have its uses, but I haven't fitted one. Main benefit on the Strat is for the front brakes, reducing chances of lock-up of the lighter front of the car until some weight transfer has been initiated.

NOTE: Locking up the front brakes is not as bad as locking up the rears when braking hard. You may (will) lose steering with locked front wheels, but can ease off to regain grip. But if you lock the rears you will find that they steer quite effectively when you thought you were going in a straight line!

Also found out recently that Hawk Cars now do an ally four-pot caliper that is an exact replacement for the Princess 4-pot (others that had been sourced for this did not apparently fit on original mountings, so what's the point of those?)

[SUSIT]

Also found out recently that Hawk Cars now do an ally four-pot caliper that is an exact replacement for the Princess 4-pot (others that had been sourced for this did not apparently fit on original mountings, so what's the point of those?)


John, do the Princess 4 pots fit on the Fiat mounting points without an adapter plate?

[rutthenut]

John, do the Princess 4 pots fit on the Fiat mounting points without an adapter plate?

No, 'fraid not.

The mounting bosses need cutting and moving out - position will also depend on the disc being used. A new mounting plate could also be made up.