Ok, an update - been a while.. Quadra has been hibernating for a while now.
I decided to replace Andy's master and slave as they were only ever on loan. Looked into various possibilities and decided to follow Jo and others with the Wilwood brake master solution...with a difference.
So I purchased one of these, a 0.625" Wilwood compact cylinder
Once received it was time to do some careful measuring. As the Renault master has studs of M7 and the Wilwood has holes for M8 bolts there was going to be some fabrication work needed.
Jo had told me that he used the original push rod from the Renault master on the Wilwood. I was looking to do this also (as seem in the above picture), of which there are two options. Drill out the turnbuckle to M8 and attach to the Wilwood threaded pushrod. Or use the original Renault pushrod in its entirety.
However, the Wilwood, once in place would protrude excessively into the footwell, not to mention modification need on the pedal box to accept the M8 fixings - if left as is would cause the pedal to over sweep causing damage. A solution was needed...
Take one piece of 12mm flat bar, 45mm wide. Mark out Wilwood fixing centres. Take said piece of metal to work, load it in the lathe and bore the mother out.
Bring it home and drill out the M8 fixing holes and tap them also.
Screw in two M8 bolts, not quite all the way down, soon to become studs.
Flip it over and weld them in place
Notice the weld which has filed flat, now mark out the fixing dimension for the original Renault master/pedal box. Drill 3/4 of the way through, and tap to M7. You can just see that I had to drill into the just welded M8s.
Cut some M7 bolts down to stud length and stud locked them in. No pictures of this though.
Now I have a spacer for my Wilwood which brings the cylinder out from the foot well bringing it back inline with that of the original. No over stroke issues!
Fits lovely, only it needs to be shaped. So out came the angle grinder and various files. Resulting in this.
Ok so armed with this I was itching to get it on the car. Speaking with Jo he told me that he uses banjos on his setup and decided this would be the only realistic option due to space issues.
The inlet and outlet off the Wilwood are in reverse compared to the Renault original.
Anyway off to the local hose shop to have a modified hose made which banjo fittings on the master end.
Got it all on the car and bled, pedal felt lovely.. was very excited. I may have a very cheap solution to the hard to come by Bendix masters.
Started her up, popped into gear and the biting point was very very low, like on the floor low. hmmm.. anyway left it there for the moment.
Did some calculations based on the master cylinders that Wilwood offer compared to the original Renault. Here are my father and my findings.
Wilwood offer this master in the following sizes.
0.625"
0.70"
0.75"
As we measured the Renault master in mm, we first converted the imperial sizes to metric, giving.
0.625" - 15.875mm
0.70" - 17.78mm
0.75" - 19.05mm
Renault MC - 18.8mm
Next we had to measure the overall stroke of the Renault master, which we worked out to be 33mm. Looking at the specifications of the Wilwood you can clearly see that the stroke is greater. Wilwood stroke is 35.6mm.
This put my mind at ease and this method will not result in any cylinder damage due to over sweeping.
Looking at the bore sizes above it is clear that the 0.75" is closest to the Renault master, a fraction larger infact.
The swept volume of the two are as follows, calculated on the original 33mm Renault stroke.
Renault - 1949.0440822871077251422239549866 mm3
0.75" - 1974.9622216792235193595407628987 mm3
After fitting, the pedal feels just as good but with a more reasonable biting point.
Next I started looking into slave cylinders.
My father visited Florida to do some maintenance on our villa and whilst out there I was busy looking around for cheap stuff for him to bring back.
I happened to stumble across the good old Delorean websites again. Slave cylinders, BRAND NEW, direct from Texas.
Well.. the Delorean uses the UN1 so must have a similar setup. Taking a gambled I ordered a couple.
And this is what arrived.
Some more pictures once back in the UK.
21 slave above.
That looks pretty damn similar to me!!
Only issue being, they use a bleed nipple directly into the slave, where Renault have bored it out to M10 and run the remote bleed pigtail.
I am going to have to drill out the Delorean replacement. More to come on this...
