Front Brake Disc and Calipers

Moving on from fitting the clutch cable, I turned to getting the front brake discs and calipers assembled and fitted onto the hubs.

These are reconditioned calipers from GBS fitted to new grooved vented discs.

Fitment seems straightforward... disc goes over the hub bolts and this in turn is held in position with a couple of wheel nuts. (the countersunk hole in the disc is a puzzlement, not sure if I should be doing anything with that, although there is no hole in the hub for this to align against in turn take a bolt/nut..?)

The caliper bolts to the hub with 2 x M35 bolts - I noted some builds have found the bolts bind on the disc when tightened up and may need a washer to pack out -I did not seem to have this issue, so left with no washers

Finally I connected the braided brake hose to the caliper.

above repeated for both sides - All that remains is for the brake pads to be fitted, brake fluid filled and the brakes bled - subject to any leaks in the union joints on the cooper brake circuit we should be "good to go" on the braking.

Remote Brake reservoir kit

Following on from the battery tray installation, attention turns to the brake reservoir which needs fitting to the master cylinder.

Now, in previous builds, the standard donor part for the brake reservoir has been the Sierra brake reservoir which simply pushed onto the master cylinder. The availability of those in the marketplace has virtually dried up, the odd one appears on Ebay but new, reconditioned ones are virtually impossible to find and when one does come available they seem to go for silly money.

GBS have addressed this shortage by developing their remote brake reservoir kit which is essentially a reservoir which fits to a bracket on the firewall and that in turn feeds the master cylinder with fluid through a couple of pipes/fittings - a nice solution:


so to get this fitted you need to:


Rivet the bracket which holds the reservoir onto the firewall

Drill out a couple of holes (+/- 28mm) in the side of the pedal box, apply a couple of rubber grommets and pass the piping through from the reservoir to the master cylinder.

Attach a couple of fittings to the top of the master cylinder which in turn the rubber pipe pushes onto.

Jubilee clip all the pipes to the fittings

Drill a further hole into the firewall to pass the wiring for the brake reservoir through to the rear.
Job done!

Rear Brake calipers

With the refurbished driveshafts now installed back into the chassis I can turn my attention to fitting the rear brake calipers.

I have elected to run with discs all round the vehicle so although the sierra donor was drum braked on the rear, converting to discs is a straightforward option.


You will need to order some rear caliper mounting brackets from GBS which fit to between the hub carrier and rear uprights. These in turn support the brake calipers via x2 M10 bolts (approx 40mm)

Brake calipers....this was a frustrating delay more through my own lack of knowledge on Sierra calipers and general guidance out on the web.

What you will need are Sierra Cosworth 4x4 brake calipers NOT Sierra Cosworth brake calipers - spot the subtle difference...yep "4x4" it does make a difference believe it or not. The standard rear discs are 22mm thick, these are too thick for the standard sierra cosworth calipers, which I discovered much to my annoyance when I came to fit! grrgghh

So what was initially a two week lead time on the calipers turned into a four week lead time by the time I had returned the incorrect ones and the supplier had sourced the correct set.

I must mention at this point the service provided by Biggred - they provided an excellent service, the quality of parts I got from them were first class and are well worth checking out both on their ebay shop and company website.

So once received, its a simple case of fitting the disc onto the hubs which in turn is secured with a wheel nut. Marry the caliper to the mounting brackets (you will have to file the carriers and remove the powder coat as the disc will foul in the caliper otherwise)

Once that is done, you can connect the brake cable to the caliper, via simple hook and eye connection and screw in the brake line, job done!

Brake and Clutch Pedals - Part 3

It seems an ago when I first picked up these two parts and assembled bushes into the chassis and respective pedals.

Now I have got some of the more fiddly, hard to reach carpet fitted it seems as good a time as any to think about fitting the brake and clutch pedals into position.

The two pedals pivot from a central shaft which runs through the bushes of each pedal, with spacers between the bushes. 

The last larger spacer on the left (as you look at the assembly from the front back) needed some trimming in order to fit into the remaining gap but that aside these all went together well.

The brake master cylinder pin still requires shortening to length but until I have got the brakes fully setup I cannot finalise this length with any degree of confidence; but fitting these two pedals into position gives the chassis a more purposeful look and you can begin to visualise the driving position more clearly

The accelerator pedal fits later in the build hence why you cannot see it in the pictures below

Brake lines

Feel some momentum building up now, I know I have laboured on about the differential getting fitted but it really was a landmark n the build and allowed for other aspects of the construction to move on.

So back to brake pipe routing whilst everything is accessible.

First one I installed was the rear to front run which follows a route down the transmission tunnel from the rear splitter to the master cylinder. I elected to start at the splitter which on reflection was probably not the ideal start point as there is alot more bending over and under chassis frame as you route towards the master cylinder.

Space is also a consideration at the rear as alot of services need to pass through a tight gap - handbrake cables, low pressure fuel hose, wiring loom etc so I was particularly conscious in ensuring I left sufficient room at the rear when routing the brake pipe.

It proved useful to temporary fix the pipes with cable ties until I have settled on the final positioning so i have some flexibility left/right/up and down before firming up and P-clips into position - again all the more important bearing in mind the tight space at the rear.

What I did come across reading a fellow builders blog was the master cylinder holes need marrying with the correct pipe run:

• Front hole nearest piston - rear brake line
• Middle hole - Off side brake line
• Lower hole - nearside brake line

realising the error in starting at the wrong end in routing the rear pipe, the offside pipe I started from the master cylinder, routed to the transmission tunnel followed round the footwell panels, over the steering column and down underneath the chassis rail toward the front of the chassis, again all temporary fixed into position with cable ties

Final pipe, the near side routed from the master cylinder, across the transmission tunnel round the footwell panels and again down the underside of the chassis rail to the front.

**important**

In routing the rear pipe to the master cylinder when you get to the master cylinder ensure you have the pedal box panel and fire wall to hand to check the pipe does not foul the bodywork - this will save some grief later on down the build if the bend on the pipe is at too greater a radius that it catches the pedal box  

Handbrake

Nice easy one to get installed and passed away an hour!

I ordered the full kit for disc brakes from GBS which comprises:

• handbrake
• handbrake cable
• 2 x brake pin
• link bar
• nuts, bolts, cable clips

all quite simple to put together, insert the handbrake cables through the chassis locating holes above the transmission tunnel and in turn route to either side of the chassis, locating a rubber grommet into a hole within the chassis frame next to the braided hose/rear pipe connection.

Connect the cables to the handbrake via the link bar and brake pins (ensure the r-clip is underneath not on top).

Secure the handbrake to the chassis via the fixing position above the transmission tunnel.

one handbrake installed...

rear brake pipes

Whilst waiting for the heavy labour to arrive and provide assistance to the differential fitment thought i would turn my mind to the rear brake pipe installation.

so what comprises the rear brake pipes..?

4 way brass union
x2 copper brake lines with male and female unions
x2 braided brake hoses 

Working in sequence, the 4 way brass union requires an 8mm hole through which a bolt with Nyloc nut holds the union onto the chassis. The existing hole in the chassis that the union should fix through is 10mm which is puzzling of GBS to provide when trawling the market for brake unions there does not seem to be a fitting which has a 10mm mounting point...

so new hole needs to be drilled to accommodate an 8mm bolt which I duly positioned top right of the existing hole. Simple drill, bolt on and job done.

Onto the copper lines next which run left and right from the brass union to the chassis mount point where in turn the braided hose connects to the chassis. These two pieces are quite short and a good starting point in which to practice the art of copper pipe bending.

Clearly there is a knack to this as the first one I did was distinctly average in its final look and I elected to replace with a new one - if a jobs worth doing right...

Lessons learned:

1. Don't strive to follow the chassis precisely, this approach does not work
2. Start with the copper brake pipe screwed into the union as that acts as a fixed point from which to bend / form and get the pipe to meet with the hole leading to the braided brake pipes.
3. Use a pipe bending tool to get a nice curve in the pipe plus it saves sore fingers doing bends!

with this knowledge in mind the second pipe running left from the union is one I am far more pleased with and is now ready for final fitment and p-clipping to the chassis.

in terms of the braided hoses, the hole in the chassis needs cleaning out with a 10mm drill bit to remove the powder coat and provide better clearance for the end of the braided hose to come through the chassis and fix in position / connect to the copper brake pipe.

so progress made on the rear brake pipes.

Fork End & Pin to Master Cylinder

I managed to grab a couple of hours in the garage Sunday afternoon following an overnight stay the previous day/night in Northamptonshire for a wedding. Not wanting to get too engrossed in anything complicated I turned to the fork end pin and considered that a quick job to tick off the list.

Basic process was to two fold:

• drill a hole in one of the pedals to take the fork and pin
• cut off and champher the bolt which goes into the brake master cylinder

So drilling first, I established an 8mm hole was needed for the pin so elected to drill to 8mm in steps, opening the hole in the pedal to 5mm, 7mm then finally 8mm.

Securing the the pedal into a vice, the drilling went well and I soon had a nice sized hole for the fork and pin to locate through.

turning to the bolt, I am conscious at this early stage I don't want to cut off too much as I don't yet know how the pedal will interact with the master cylinder and in turn how much travel will need to be applied to the brake pedal to apply the brakes! The fork does have an element of adjustment on the thread but better to be safe than sorry I chose to only remove approx 20mm of the bolt to start with - more can be done at a later date if need be.

Simple junior hacksaw to the bolt soon had that cut to size and I chamfered the end with help from the bench grinder and some emery paper.

A dry fit of the assembled fork, pin and bolt suggests as an initial start point it will be fine, the fork is screwed onto the bolt approx half way so I do have some further adjustment available. 

With this assembled I could finalise the positioning of the master cylinder relative to the bolt thus ensuring a smooth, even, level motion of the bolt into the master cylinder when the brake pedal is pressed. Once this datum had been established the master cylinder bolts were tightened up.

Job done! - a nice hours work and further progress.

Brake Master Cylinder

I took the opportunity to fit the brake master cylinder into position on the chassis. A simple task of two nut and bolt fixings. Not fully torqued up at this stage as I need to establish final position in relation to the brake pedal, fork pin and bolt which acts as the piston into the cylinder.

These all need to be lined up straight and true to optimise braking action.