rear hubs/discs

[Elanlover]

Bob, any further progress/thinking on this issue? I'm certainly interested in getting better, more relaible brakes on the back end. Sy? Did you post that "information" from your contact regarding the rear brake upgrade that he/she did????

[Elanlover]

.........There may be another space saver from another manufacturer that may fit VW spring to mind.

The Mini space saver pare can be picked up pretty inexpensively and is a 15" wheel. Might fit

[bobbrown]

I have now looked at this in some depth and it would apear that the only real contender out there for a rear caliper is a Hi-Spec one.
A 2 pot Hi-spec caliper can be incorporated with a 276mm x 24 disk and the hub I propose. this will increase the rear braking force in line with the current front upgrades
BUT the proportioning valves will need to be looked at the present they cut in at 15bar and when a front upgrade is put in place this moves the front tyre braking load up by a factor of about 50%
So to retain the correct pressure and braking loads the proportional valve needs to cut in at a lower pressure, somewhere around the 10bar not the std 15bar.
This could be achieved by changing the current units to adjustable ones, for track use it might be nice to have them to hand which is just a plumbing issue.

In any case the balance of the brakes needs to be address as the upgrades to the fronts changes the characteristics of the braking system possibly not out of the zone where they still function to some degree correctly but certainly to the wrong end of things.

[nitroman]

Just want to throw this general idea out there:
It would be nice if we could balance our R to F brakes by choosing otherwise matching (same brackets) calipers, put choose our piston size in relation to the piston size we're using in our front calipers. Wilwood is pretty good about supply a wide range of piston sizes within the "same" caliper. The dust-booted Dynalite you are considering are offered with pistons from 1" to 1.75".

Of any vehicle I'VE ever owned, the car with the best brakes hands down was my 1986 Maserati Spyder. It had 4-pot calipers & ventilated discs on all 4 wheels.

http://www.britishv8.org/MG/DanMasters.htm
Here is a first-rate "ship of the line". Notice the setup of his rear brakes, which is exactly the solution Wilwood promotes for incorporating a parking brake, i.e., 1 caliper for the road & another caliper for parking.

I have to show his front brakes too. I know Bob, that you will be drooling over his rotor choice, but at least he will die a happy man. In the end, that's the most any of us could ask for.

Such a dirty car...

[nitroman]

Here's one other thought to mind: The stock ~.5" wide rotor could be retained if Wilwood Powerlite caliper #120-8725 or #120-8724 could be bolted on. The respective piston areas (sq-mm) are:

1924 - stock caliper. Balance F/R 69%-31%
2027 - #8724 caliper. Balance F/R 68%-32%
2027 - #8724 caliper. Balance F/R 75%-25% with a Wilwood 120-6816 Front caliper
3177 - #8725 caliper. Balance F/R 66%-34% with a Wilwood 120-6816 Front caliper
* stats recalculated to reflect a 52mm piston OE front caliper.

The smaller #8724 caliper will approx. match the stock brakes, whilst the larger #8725 caliper will pair with the larger Front #6816 caliper which almost all 16" users have. As these 2 calipers have identical external dimensions they can utilize the same bracket & just be ordered as one's situation indicated.

I would think retaining the rear discs ideal.

[bobbrown]

Firstly I do not like drilled discs!
I do not have a problem using a spot caliper for the handbrake but it does add to the cost.
I was thinking of a two pot rear or a small piston sized 4 pot but have yet to do the complete calculations.

Bob

[bobbrown]

nitroman

There are a couple of issues

The 6816 is too big for the current master cylinder never mind adding more area to the system, (long pedal travel)
No dust seals in the Powerlite in Dynalite calipers. the Dynapro's have dust seals.

In your figures for brake balance have you taken disc diameters and pads into account as I do not get the same figures as you and can not get any where close to them!
I can get quite close using a 294mm disc on the front and a 4pot 1.5" and 260 mm disc on rear and a 4 pot 1.25" which gives close to 70/30 split

Bob

[bobbrown]

I have the final drawing just about finished and I am in the process of maching up a prototype.

Before I go any further with this I need some feed back, like who would be interested, not much point if it is not wanted!

The object is to get rid of the one piece disc/hub assembly and replace it with a two piece setup that can retain the standard rear brakes as shown in the drawing (discs from Corsa/Astra 1990 to 1999 from £28.00 the pair ).

hub assy1.jpg

hub1a.jpg

Then as the discs wear go rusty etc it becomes a lot cheaper to replace not like the £150.00 + bearings and seals it is at present.
If you are contemplating replacing the rear discs then this seems like a good way to go as I hope to keep the costs similar to the current setup but even if it comes out at say £200.00 at least you do not have to replace the hub again.
It then has the advantage of allowing the fitting of other rear brake set ups Hi-spec ( http://www.hispecbrake.co.uk/Start%20SVA.htm ) , Willwood etc

[lotusgirlmarie]

REAR BRAKE HUBS
1Bobbrown
2 LGM
3
4
5

[Monty]

For me it depends on price as i`ve still got to pay off my current Upgrades


REAR BRAKE HUBS
1Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5

[Nige]

REAR BRAKE HUBS
1Bobbrown
2 LGM
3 Nige
4
5

[Monty]

Get in line boy


REAR BRAKE HUBS
1Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5

[Nige]

[paulwatkins]

REAR BRAKE HUBS
1Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins

[L.G.]

REAR BRAKE HUBS
1 Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins
6 L.G. (Hubs only at the mo)

[bobbrown]

If there is enough interest and this goes the distance which it appears to be doing I will get the Hubs anodised
I will only do it in one colour (it cost more to get them done in different colours) so the choice of colour is up to you guys, grey, red, blue, pink if you really want.
A vote on colour may be

[Monty]

Just keep`em Black

[GeoffSmith]

May well be interested as I had an advisory about pitted rear discs.

[bobbrown]

May well be interested as I had an advisory about pitted rear discs.

Thats one of the problems, I have a set of used discs that came off mine not so long back and although they are still ok on thickness the pad running surface is scored and is more rust than nice shiney metal.
I did consider skimming them but it is something I have never liked, once they are past there best then a float test is called for (very deep water, if it floats it's ok).
I did not want to spend £200.00 + then next time I came to do this hence the alloy hub + Vauxhall discs
Once you have a hub that does not need to be changed then the £50/60.00 for new discs and pads is not so bad.

[GeoffSmith]

REAR BRAKE HUBS
1 Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins
6 L.G. (Hubs only at the mo)
7 GeoffSmith

Float test.......