Archive for month: October, 2018
- 13/16 socket wrench to remove caliper bolts and heavy hammer to get it started (not sure why this is Imperial, not metric, but 13/16 worked the best)
- 7/16 open wrench to remove brake line (or vice grips if either the nut or line is shot and must be replaced)
- Wire cutter to cut split pin (cotter pin)
- 13mm socket wrench to remove shock absorber bracket
- Small bucket to collect dripping brake fluid
- Heavy welders gloves to protect hands when a frozen bolt breaks free and smashes your hand into something hard and sharp
- Magnetic back light that can be positioned inside the wheel well. I bought a strong LED light at the hardware store and a round 65 kg magnet that I bolted to it
- After the health and safety lecture on what you need to do to jack the car up and remove the rear wheels, position the light so you can see the inner workings of the brakes
- Cut off the split pin that holds the emergency brake on, remove the pin and remove the cable controls
- Unbolt three bolts holding the shock absorber bracket to the axle. Note that the inner one may be hard to access if you leave the shock on the bracket, with the alternative of removing the shock
- This gives you room to unbolt the two heavy bolts that hold the caliper to the axle
- To loosen the heavy caliper bolts, use an extension bar on the socket wrench, or gently tap the wrench with a heavy mallet. Wear gloves
- When the bolts are loose but not yet off, shift to removing the hydraulic brake line that goes along the axle. If badly corroded you may find you have to sacrifice it using vice grips and flare a new pipe when reassembling. Wear gloves
- Position the bucket under the pipe, it will slowly drain
- Remove the heavy bolts and the brake calipers should come off.
For the most part, this is a standard job, except that the emergency brake and the shock absorbers get in the way.
In my case, the car had been rebuilt 14 years ago and then garaged, so bolts and nuts came apart reasonably easily. For most Bristols, you may not be so lucky. On reassembly do yourself or the next owner a favour… use anti-seize compound.
Here is how to identify if the brake lines are blocked and what to do.
- New hardware store oil can (metal tank with pump squirting lever and 1/4″ solid tube) See amazon.co.uk/dp/B000LFTT5Q for an example
- New hardware store 6mm clear plastic hose (3 metres) and several hose clamps to fit
- New brake fluid
- Kunifer brake line (a soft alloy also known as cupro/nickel) 3/16″ SAE and male & female flare tube nuts to match the Bristol thread
- Brake flaring tool that does double flare
Remove the driver’s side (RHD) brake tube flare nut (male) from the T section. Temporarily you will be replacing this with a test brake tube flare nut. BTW, if you don’t know how to flare Kunifer brake line, it’s forgiving and easy to learn. Get the tools and watch a few YouTube videos or buy a case of beer and stop by your brake supply shop half an hour before closing time for a tutorial.
Make up the testing tool:
- Slide the clear plastic hose over the oil can tube and hose-clamp it tight
- Take a section of the Kunifer brake line (say 300-500mm) and double flare one end with a male tube nut that will go into the T section.
- Put a similar double flare on the other end and slide the clear plastic hose over. You will need to use the host clamp on top of the flare to keep it from leaking under pressure.
- Slide the other end of the clear plastic pipe over the oil can and hose clamp it.
- Fill the oil can with new brake fluid (this is why you buy a new oil can… no contamination)
- Open the bleeder valve on the opposing side of the rear axle (left/passenger side on RHD). Attach a hose into a clear glass jar on the ground that you can see from your side.
- Pump the can. If fluid comes out on the opposing side, you know the rear axle lines are clear. You might as well keep pumping until the fluid is clear, you’re doing the equivalent of a bench bleed.
- Close bleeder valve
- At the front end of the car in the battery compartment, disconnect the battery to avoid sparks and then disconnect the brake line leading into the servo that connects to the rear brakes and pump again. If you are unsure which servo, climb under the car and follow it from the back to the battery compartment.
- In theory this would reverse flow brake fluid forward until it dripped out (have a cup or big towel ready to catch pumping brake fluid (or make up and attach a female nut to metal line to plastic hose to glass jar)
- If it does nothing (no flow from the front brake line), remove the rubber flex hose that connects the body brake line to the axle brake line. This probably is the culprit (it was for me). Try blowing air through it. If no air, you know it is junk.
- Then hook the testing pump to the metal brake line in the battery compartment . If fluid flows out of the rear line where you removed the rubber hose, you can presume the metal line is OK.
- You can also mechanically test this if you have a new stainless steel bicycle brake cable wire that you slide inside the car’s metal brake lines. It should come out the other end clean and with no resistance.
When doing this job, make sure you know where to buy replacement Kunifer brake lines and matching nuts because most cars will not come apart easily. Nuts may strip, or if frozen may twist the old metal lines, requiring replacement. A brake supply house should carry both the metal lines and the rubber hose. The 1970 411-S1 hose seems almost identical to “H892 Hose for British Ford, Hillman and many other British cars” (try also GBH136). Try Powertrack for parts.
Note: Even if you don’t live in New Zealand here is some useful advice!
Having checked everything people have suggested to improve my cooling with no change, I pulled the rebuilt radiator and the water pump and took them to Trevor French Radiators in Auckland (www.trevorfrenchradiators.co.nz ).
He saw nothing wrong with the water pump, so he suggested that he unsolder the radiator and check it out. First they put a hose into the top, and water flowed out the bottom, but he said that did not mean that it was travelling through the cooling fins. Not sure I understood that one, but as it turns out, he was correct.
For a fixed fee of NZ$90, he completely disassembled it and found the engine rebuild resulted in debris that had blocked the reportedly rebuilt radiator. He rodded it out and soldered it back together. He began at 2 pm and handed it back to me at 5 pm with a fresh coat of black paint. He also recommended that I take a woman’s nylon stocking and put it over the entry of the upper hose to catch any more debris.
He also said that the radiator design was quite good… more sophisticated in construction and should last another 30 years before needing attention.
On reinstalling it, I hooked up a second capillary temperature gauge and discovered that the Smith’s gauge was reading 140 C while the aftermarket gauge was about 93. Without that second opinion, I probably would have presumed I had not cured the problem. Unlike previous runs, the engine was not making those noises related to high temperature, so I am more comfortable that it is running in the 90’s. The fans going off and on seem to agree,
After a few runs up and down the hill, I pulled the upper hose off to inspect the nylon stocking. I found significant debris, blue engine paint and other junk that would have contributed to the need for a 3rd disassembly of the radiator.
Advice to others in the future…
1. When you install a newly rebuilt or cleaned radiator, or if your car has been sitting and may have built up scale in the engine block, use the nylon stocking trick to protect the radiator.
2. If the car overheats, it is easy enough to remove the Bristol radiator and have a shop take off the top to check for any obstructions to water flow. Even if it was just rebuilt, it could be blocked again.
3. Do not rely on the Smiths temperature gauge. The engine block has nearby places to add a second temperature gauge, which costs less and is more reliable than an infrared gun.
4. Other advice they gave was to never use a water blaster that comes near the radiator fins. It flattens and does damage. I’d never given it much thought, but it makes sense. He showed me an example.
Finally, anyone in NZ needing radiator work, these guys are highly recommend. Three older fellows, all white hair, the oldest radiator in the shop was from a 1927 Alvis. Good prices, great service, super knowledgeable.
The following contact details and addresses are for companies who undertake supplying spares and who conduct strip and rebuilding of automatic gearboxes (ie Torqueflte) and Salisbury axles.
- American Auto Spares Ltd., Kingsbury Road, Minworth, B76 9DD.
Telephone:- 0121 351 7655. Contact: Phil
- VMTP Midlands Ltd., Unit 10, Conduit Road, Norton Canes, Cannock, Staffordshire WS11 9TJ.
Telephone:- 01543 270555. Contact: Nigel Bishop
- Penn Autos Ltd., 3 Spring Lane, Wolverhampton, WV4 4SH.
Telephone:- 01902 344004. Contact: Andy Frost.
American Auto Spares Ltd. no longer conduct strip and rebuilds but can provide most engine, gearbox, starter motors, alternators, etc. which is now the focus of their business.
The others are renovation companies who have conducted strip-down and rebuilding of Bristol V8 gearboxes and axles in the past and felt confident in ensuring a good outcome.
They always prefer to have the vehicle and are quite prepared to remove the gearbox which is taken out from the inside of the car and replaced. Both stated that the final adjustment to the auto-box is best achieved by a series of road trials.
The axle can also be stripped whilst still assembled to the vehicle saving the cost of removing it and the shipment cost of transporting such a large and heavy item.
Mobile Windscreens Bristol who trade under the name of National Windscreens at Bristol can supply windscreens. The manager there is Mike Ackerman (Mike.Ackerman@mobilewindscreens.co.uk), tel 0117-3042000. They have in stock heated and normal 411 screens. He states that these fit 408/9/10/11. He will supply and pack a screen for you but requires you to sort out the carrier.
The rubber seals are stocked by Bristol Cars Services who say that seals cover 408/9/10/11. Graeme Payne (mob 07787-138079) is the contact there and confirms that all are covered.
The other company who may have everything is American Cars Care Services Ltd, owner Martin Barnes (mob 07769-906525) firstname.lastname@example.org . He has some 408 screens in stock and states that 408/9/10 all have the same screen but the 411 is different.
One of the features of age is that I can remember many things from a long time ago – but not always accurately. My first memory of disc brakes was in the 50s as a young apprentice mechanic in the nearest Morris/MG Distributor to Fort Dunlop in Birmingham. Their development department used us as a fitting service for their test cars. In particular they had an MGA 1600 to which I fitted more sets of hydraulic cylinders than I care to remember as they attempted to make the pull back mechanism work (they never did). I well remember the constant exasperation of the Dunlop engineers, their cynicism and their bad opinion of their own product.
Even though in recent years I have fitted Dunlop brakes to four Jaguar XKs and my own 406 my prejudice has stayed with me to this day and I have never felt comfortable with their performance or durability. Imagine my joy to discover that there is now an answer. Zeus Engineering now makes front calliper sets and rear cylinders to modern standards and high quality.
Their product fits with little complication and additional pipework plus adjustment shims and instructions are included. One small point is to be careful to centre the calliper over the disc; my car had significant variance side to side.
I have now bedded in the pads and find the brakes to be powerful and progressive in the manner of a modern car. Beyond that I no longer have the comments of disgruntled Dunlop engineers ringing in my ears.
Unit J2, Dunkeswell Airfield
Devon, EX14 4LE
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