Section XVII Brake Pipes

Warning:- Before carrying out any modifications to the standard design seek written approval from the Kit Designer. Use only high quality materials and fasteners and lock all threads. This applies particularly to Safety Critical items such as Brakes, Steering & Suspension Components. Do NOT use threadlock or any other type of sealant on brake unions, pipes or fittings.

Safety Note:- When cutting and flaring pipework extreme care must be taken to unsure that swarf etc. does not get into the pipework. Cut the pipe using a fine tooth saw, and remove all burrs with a fine file. Blow out any swarf. Use a proper bending tool and keep bends as large as possible. Avoid kinks. Support all pipe runs with proper insulated clips at regular intervals. Between 8" & 12" is recommended. Maintain the highest standards of cleanliness and sound engineering practice. Check that installed pipework cannot rub or chafe under any conditions. Ensure full and free movement of all flexible pipe runs for the full suspension travel, i.e. Front Wishbones & Rear Swinging Arms. If in doubt ASK. Brake failure can cause sudden death.

The brakes fitted to the Standard Ford Sierra are perfectly adequate for all NORMAL road use, the Sierra was a much heavier car and did of course meet and no doubt exceed all design criteria. If you intend to race or modify the standard brakes in any way read no further. This section is not for you. Try the Speedpro Series.

Rear Disc Brakes and ABS are not covered in this manual.

The use of second-hand brake parts straight off the donor is not recommended, as they are probably past their prime. As mentioned in other chapters a full rebuild of the Rear Drums and the use of new or replacement Disc Caliper's is the ideal solution. These items and the Brake Master Cylinder were fitted at an earlier stage and all we have to do is connect up the various bits. It would seem that Seal Kits for some Master Cylinders are no longer available. This as always is on Health & Safety issues. If the seals are worn, so are the cylinder bores.

One slight complication is the Pressure Reducing or Deceleration Valve (PLV) in the Rear Brake circuit. You are advised to fit this for the SVA but (as far as we know) it is not part of the actual test. Although it is not tested, it does form an important part of the braking system and it is strongly advised that one is fitted. A sports car with a light rear end can be prone to rear brake lock which can be very dangerous. During moderate to heavy braking this valve reduces rear brake hydraulic pressure thus preventing rear brake lock, a bit like a poor mans ABS. The only way to adjust the Sierra unit is by altering its angle relative to the road, once fitted this is not easy. As a start fit it in a position and angle more or less as the original Sierra. Another solution is an adjustable valve, and this type of valve has been the subject of an article on the RHOCaR web site by Dave Andrews. It is based on a valve originally fitted to the Austin/Rover Mini.

Some copper pipes are supplied in the RH kit but a full set is 8 pipes, so some will have to be made "in house" or bought out.

The flexible pipes supplied in the kit are incorrect, at least for the rear end as there is no proper provision for fitting the outer ends of the pipes to the welded brackets on the swinging arms.(The original Ford fitting used a spring clip) The front pipes are not much better, as there is barely enough thread to pass through the Nose Cone panel, fit a Panel nut and the Union. The simple solution, at least for the outer rear unions, is to make up a special stepped washer with a 10mm hole and a flat that fits snugly into the Sierra bracket, and simply bolt the pipe to the bracket using a thin nut. This end of the pipe as supplied in the kit is designed to fit into a brake slave cylinder and has a 90 deg external form on the inboard end. They normal " mushroom " flare seems to seal up to this quite well. Make sure the female union will run fully home without fouling the thin panel nut. See the close up photo. Make up a couple of copper pipes using the original Ford pipes as a pattern, with male & female unions, and fit to the rear brakes and swinging arms as on the original car. Fitting the Front & Rear Hose inners is a bit more problematical as the threads are just too short. One answer is to use a thin top hat nut that is screwed or pop riveted to the panel. This gives us an extra 0.7mm of thread as the nut now passes through the panel. See the AutoCAD drg. Use a piece of rubber insulating tube on the swinging arm knock down clips. Note the male union at the rear drum back plates is very close to the bend.

If you decide to make or purchase a new set of brake pipes Appendix IV gives full details of all 8 pipes required and also the specification for a new set of Goodridge Stainless Steel Braided Hoses (4) which will solve all of the above problems regarding thread lengths and end fittings. Automec can supply a full set of copper pipes to these sizes at a special price and can also supply the Goodridge Hoses. All unions are 10mm x 1mm Metric Fine either male or female. The flare is the same on ALL ends, particularly if you use the new Goodridge Hoses.

If you do decide to fabricate your own pipes the best procedure is to first accurately determine the pipe length and then add 1/4" to allow flaring. Flare one end and slip on the correct union. Slip on any sleeves or rubber grommets. Slip on the second union and swage the second end. Ensure the pipe is free of dust and swarf etc. and fit one end to the car. With the other union at the far end of the pipe form the pipe as required and secure at regular intervals. Note that male unions will not pass round even the slightest bend. Good flare tooling is expensive if you are only building a one off, and some of the cheaper tooling is more or less useless if you are working to reasonable standards of safety and workmanship. It is cheaper and safer in the long run to buy a ready made set.

The Inner ends of the rear flexible pipes continue to the Sierra 3 way union, via two short lengths of copper pipe. The 3 way union is secured to the chassis with a large self tapper or bolt and some additional positive support is required for the inner ends of the flexible pipes. Make sure the flexible pipes have plenty of freedom to allow for extremes of suspension movement and do not chafe at any point of travel. This is most important as even copper pipe will wear through very quickly if due care is not taken.

The input end of the 3 way union passes down the Propshaft Tunnel (well supported) to the a Pressure Limiting Valve (PLV) and then to the Brake Master Cylinder. The standard cylinder has 3 outlets. One for the rear brakes, via the PLV, and the other two (at the front) go to the Nearside and Offside front disc brakes respectively. This is more or less an identical layout to the Ford Sierra donor apart from obvious routing and length differences. Clip all runs as required and check tightness of unions. Use a special Pipe Spanner.

The Front Flexible Pipes cannot be fully fitted until the Nosecone panels are in place, as the short threaded ends need to pass through and be secured to the panels. As mentioned previously there is really insufficient thread to do this with confidence. When the union is fully home there is only about 2.5mm of thread left leaving insufficient thread for a half decent nut. I have reluctantly come to the conclusion that the only SAFE solution is a set of new hoses properly selected for the job. There is a very simple answer to this problem but safety considerations prevent me including it here. There is a second problem with the Front Hoses, in as much as they foul the Mudguard supports, or clear them very slightly. This problem has been covered fully in Section XXVI Front and Rear Mudguards. Some owners have solved this problem by fitting a Jaguar item. Lucas Part No. PHC 201. These do however need a spring outer fitting.

Added hose clearance with spacers

All that now remains is to connect the Vacuum Cylinder to the Inlet Manifold, Connect the Low Brake Fluid Switch and fill up the system with brake fluid. If you have a totally new system you may wish to consider using the new Silicone Brake Fluid to Spec. DOT5. This is designed to give superior results over the more usual Glycol based fluids. DO NOT MIX FLUIDS. Bleed the system in the usual way (see the Haynes Manual) and finally check for leaks whilst applying full pressure to the system for a couple of minutes. The system MUST be 100% leak free and the pedal should not feel spongy, but solid. Any loss of fluid must be investigated.

We now have a Catch 22 situation as new brake linings will not give full power until they are bedded in, but you cannot bed them in until you have an MOT and SVA. I suppose a private road is the answer.

Once you are 100% happy with all the above we can finally fit the boot. This will cover the 3 way union and the exit of the Electric's and Fuel lines from the tunnel. Make sure the boot can be removed fairly easily as you may require access to these items for inspection etc.

Appendix IV gives a listing of copper brake pipe finished lengths flare to flare, (it does not include any allowance for flaring) more or less to the routing shown in the photographs. Also included is the correct specification for the flared ends and unions. This information is given for builders wishing to purchase custom made pipe work. Please double check your ends and lengths as this list was prepared from my car and details may vary. This course of action is strongly recommended as you are more or less guaranteed perfect flares and full specification internally clean pipe work, in either Copper or Copper Nickel tubing. See Automec link.

Go to Section XVIII

Back to Home Page

© Colin Usher 2005