| Author | Message | ||
     Brian Vogel Grand Master Username: guyslp Post Number: 2720 Registered: 6-2009 |
I didn't enter the world of Jaguar until 2005, with a 1999 model produced 4 years after Ford had taken over and pretty much turned the company around from the brink of ruin. Today I noticed an ad for a 1991 Jaguar XJS on Craigslist and took particular notice of this picture:  which certainly looks like an accumulator (of the SZ era, which makes sense) but I have no idea what it is for, as I don't think they ever used a brake system with them. I figured someone here almost certainly has to know whether this thing actually is an accumulator and, if so, what its purpose was. Brian | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 900 Registered: 11-2015 |
It's a brake accumulator | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2721 Registered: 6-2009 |
Thanks Ross. I had no idea any marques beside RR/Bentley and Citroen had ever done this. Brian | ||
| Steve Emmott Experienced User Username: steve_e Post Number: 25 Registered: 11-2018 |
Brian as Ross says it is a brake accumulator AKA 'the bomb' but we had nick names for various parts as did RR, MG and other engineers working in the assembly of the cars. Probably the best nick name used by MG and also Jaguar was 'Tom's knob' this was the little rubber one way device fitted at the base of the plenum for drainage and to prevent fumes getting into the interior. Aptly named as it looked like a Penis with a testicle but no one ever really knew who Tom was. RR used to call the front screen woods on a Shadow as 'hockey sticks'. Just to correct your dates though Jaguar was purchased by Ford in the late 80's actually and I joined Jaguar/Aston Martin in 1990 as a result of the need to increase new model prototype volume production and reduce new model vehicle introduction cycle times leading hopefully to overall increased sales volume which was the only way Ford could hope to get a return on their purchase investment. Indeed as well as the common use of the brake accumulator across these brands Jaguar at this time also used a self levelling system again Citreon's idea as did RR/B license its use. | ||
| Alan Dibley Prolific User Username: alsdibley Post Number: 175 Registered: 10-2009 |
The reason for a brake accumulator on cars with ABS is this:- When the ABS system operates the supply to the calipers is repeatedly either ON or STOPPED or RELEASED, ie. pressure applied as normal, pressure held constant (not increased) or released back to reservoir. This means that repeated demands for fluid are made in a short time. A foot operated cylinder can't do it, so the brake system needs a pump, which may not keep up a smooth supply of hydraulic pressure - hence the accumulator. If you want a late Christmas present buy yourself a copy of "Automotive handbook" by Robert Bosch. This years edition is expensive, but "out-of-date" copies can be had for a few pounds/dollars/euros...... These are fine for our interests. I bought a NOS edition 2 (1986) for about 4 euros. Alan D. | ||
| Steve Emmott Experienced User Username: steve_e Post Number: 27 Registered: 11-2018 |
It has been a long time now since I worked on these cars but this design was adopted if I recall not just for technical advances but as it all took up a lot less space than the old vacuum servo system. Under bonnet packaging space was always an issue for the design engineers. We constantly were asked by Ford to repackage the battery on the XJ6 to provide more boot volume but could never find enough space in a suitable area under bonnet/hood. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2722 Registered: 6-2009 |
Steve, Thanks for the additional information. I know what I'm remembering was the introduction of the 1995 model year XJ series, which was pretty much the debut of Ford's major influence on Jaguar on these shores. By 1999, the year of the XJ8L I'd owned, every last bit of Lucas electricals was banished and the whole design of the vehicle had taken place under Ford. I lucked out as far as living in the USA when it came to the nikasil liners. We never had 'em "wash out" secondary to high-sulfur-content fuel. I still find it rather amazing that they sold Jaguar when they did. Basically they fixed a car company on death's door and sold it off immediately after all that hard work had reached "cruising altitude" which it still does to this day. I won't own another post-2005 (I think) when the homage to the classic cigar shape disappeared. Today's Jaguars look utterly "generic" to me and don't turn my head at all. Brian, who often wonders how the location of the battery came to be the boot/trunk in the British car industry | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2026 Registered: 9-2004 |
"Brian, who often wonders how the location of the battery came to be the boot/trunk in the British car industry" Heat!!!!!!!!!!!!!!!!! | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2724 Registered: 6-2009 |
So? The vast majority of the world's car makers don't do this, so I'm not even buying that it's an issue. Decades of driving cars with batteries in the boot/trunk and in the engine bay have shown no functional difference in battery life. Brian | ||
| Steve Emmott Experienced User Username: steve_e Post Number: 30 Registered: 11-2018 |
Brian, Technically Patrick is correct as it was always the argument used by the battery specialist department to package the battery in a 'cooler' environment. There are lots of cars though with underbonnet batteries and it would have been quite acceptable to package the battery at the front end on either side of the engine bay where cool air would flow (like say the VW new beetle) and certainly save the weight of the copper wiring required to take the high current all the way from the boot through the firewalls and into the engine bay for the likes of the starter motor. Trouble is nowadays homologation regulations in certain countries insist that lights/lamps have to be easily accessible and be changed at the roadside if blown. Again the reason why in some countries you have to carry spare lamps/bulbs as a legal requirement. This then made it very difficult to place the battery in these frontal areas and especially even more so on 'sleekly' designed cars. I agree though there are also many older cars like the Triumph TR where the battery is virtually central just behind the engine. Being retired now for 15 years I don't know how the modern LED lighting must have changed things especially where you have multiple LED strip lights so if one LED fails there are still lights. I agree re the nikasil liners it was a disaster period but vehicle weight played a big part in the 'gas guzzler taxes' and overall vehicle weight here was the reason. I have nickasil lined in the Lotus Esprit Turbo engine and as it approaches 60k miles I have to admit it won't be long till work will be required. Still at my age now it is getting harder to get in and out of so maybe time to let it go. As I enjoy my pension and a new Jaguar/LandRover company car each year in retirement from the many years I spent at Jaguar/AM then what became the Premier Automotive Group which included Jaguar, Aston Martin, Volvo and Mazda and then Just Jaguar/LandRover all under Ford Ownership (Mazda partial ownership) I feel I have to keep my views personal especially as this site shows our real names. I retired early just before Ford sold JLR to TATA and am pleased that TATA has done very well with the brand names, albeit, I think now some difficult times looming in the UK car industry are just about to hit us. I do miss my time though I spent with Ford in Detroit, Michigan........ | ||
| Omar M. Shams Grand Master Username: omar Post Number: 1771 Registered: 4-2009 |
Dear Brian, You would be surprised how many cars have accumulators as part of their braking system. Apart form Jaguar, Range Rover also use these for the ABS systems. I have on on my 1993 Range Rover Vogue LSE. | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 901 Registered: 11-2015 |
Brian, I had a 91 Vanden Plas which had the accumulator for the brakes as well. My f250 ford diesel pickup has one because diesels don't have vacuum so for power brakes you have to either run an vacuum pump and a booster or power the brakes with power steering fluid pressure which means you need an accumulator. The power steering fluid option also lets you generate over 2k of line pressure which allows easy stopping of heavy loads. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2027 Registered: 9-2004 |
Ah, blame the nikasil, the main failing fault was in the fuelling system washing the oil from the cylinder bores.. Some manufactures tried blamed the fuel! The French C6 has the battery in the boot as do many moderns for a cooler environment. Accumulators my C6 has 7 but not one fitted to the braking system. BMWs and many moderns now have them. As for "Decades of driving cars with batteries in the boot/trunk and in the engine bay have shown no functional difference in battery life." Step up a gear to the real world, with regenerative braking stop start Etc the manufactures even go to the trouble of battery cooling in boot trunk location. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 2725 Registered: 6-2009 |
Patrick, Again, I say black, you say white. Entirely predictable. If a boot location were significantly better for battery life it would have become universal decades ago. It hasn't. It hasn't even come close to doing so. That speaks for itself. Brian | ||
| Steve Emmott Experienced User Username: steve_e Post Number: 33 Registered: 11-2018 |
Patrick it is not a definitive statement to say modern cars will all follow a policy of battery in the boot really as there are still many modern cars with the batteries underbonnet. My last 3 new LandRovers have stop-start and the battery has been packaged underbonnet above and behind the engine. The fact a cooler environment though for the batteries is I agree the better solution but not always fully achievable in vehicle designs. There are compromises needed to be made and the Battery department would always want the coolest condition possible. Believe me I have spent many hours arguing both sides of battery locations in new model vehicle designs and listened to all the arguments from rear end impact crash safety, voltage drop from back to front, weight/cost of cabling, etc etc etc..... The problem today in large companies is self preservation of budgets as warranty claims get charged back to the specific component design department so each department will strive to protect best their own interests, but at the end of the day some positions of components have to be generic in location but for the remainder of parts that can be packaged sort of randomly the battle for space begins. I recall having to change the position of the horns 10 times or more as the early designs progressed. It may appear a simple thing to find a space for but the poor electrical harness department designers would have to virtually start again on their designs to provide the 12v feed. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2028 Registered: 9-2004 |
Now that a controller area network has saved the cost and weight of the electrical harness with the added bonus of little or no voltage loss most batteries will be fitted in the coolest environment, this is the norm now with cars running stop start and brake regen alternator outputs in the 300amp with the liquid cooling etc. As for Land Rover who in the heck did the designing, having to lift the body off a Range Rover to carry out a simple turbo change..... As the years go by bolts snap etc will make the things worthless! Total waste of money. | ||
| Steve Emmott Experienced User Username: steve_e Post Number: 34 Registered: 11-2018 |
Like I said Patrick everything has to be a compromise and every department at the concept of a new vehicle will be represented and that includes the Service department too. Their role/input is to challenge any proposed future design relative to their own experiences of faults in service. Like Ferrari 348/355 onwards you have to remove the engine just to change the timing belts. That sucks as it is recommended every 2 years these belts are changed. I have hung on to my 1978 F308 as thankfully I can do these with the engine in situ....... Jaguar X400 (some models)...Porche 911 too require engine drop to just change spark plugs.....the view is plugs can now last for 10-20k miles so not I suppose by them really considered as a big issue. Indeed first sevice required now for many cars can be around 10k miles. For someone like me I would not want one of these cars as I have no facility to even consider doing an engine drop just to change spark plugs. Old classic Lotus Europa twin cam..... engine out just to change a water pump.... the list could be endless with these frustrating designs. I would hope a Turbo though would last even longer miles so sort of becomes insignificant I suppose when compared to other manufacturers peculiar designs. What does need to be considered for anyone not correctly tooled up with the right equipment as designed for a main dealer who is servicing the marque is any job can always appear time consuming to the non franchisee or DIYer without that specialist equipment. Technicians in the factory workshop could drop an engine/gearbox out and replace it in a couple of hours. A Turbo.... probably in their coffee break  If all this bothers you then certainly even a classic RR/B is not a marque to choose as just to change a simple relay in lots of places or the coolant light amplifier for instance can require some time consuming strip down... all the dash/facia wood and dash/facia top roll has to come off. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2029 Registered: 9-2004 |
Yes the LR service department, ok while the vehicle is on warranty in the early years with the servicing being a doddle. After the warranty and as the years and miles progress the LR main dealers do not want to know. If you can lever them to carry out a repair job the cost becomes horrendous, good for the independents though. Cost of a LR coffee break body off 2.7 turbo change quote: £1950.00 without the cost of egr valves cripes! Classic Rolls Bentleys have stood the test of time, service and repairs as needed with the most jobs being carried out by the enthusiastic owners if they want to do it themselves and spares at a realistic price. Testing a relay and removing the dash panels etc is nothing to fitting a graphic equalizer booster into the system, what sound with such a quiet running motor. Even the battery is fitted in the correct place with a Lucas starter motor that flies at cranking speed when all is well with a 60amp charging system with alternator! If the Shadow had more ground clearance it would almost be a match for the new LR range as a long term work horse with the limited slip diff etc working correctly, however todays LR IMO will never make it long term because of repair costs sending them to the scrap heap. | ||
| Steve Emmott Experienced User Username: steve_e Post Number: 35 Registered: 11-2018 |
Patrick, I don't want my posts to be used as a sounding forum for you to exude your frustrations or knowledge or even lack of it. If you are that inclined you would have worked out by now that you don't actually need to lift the body to change the Turbo on a LandRover/Range Rover........that said it is however the correct factory recommendation to the dealers. Check out this link https://best-turbos.com/land-rover-turbo-replacement/?gclid=EAIaIQobChMI9ZD75pHA3wIVCJ3tCh0-bwXCEAAYASAAEgIJ9vD_BwE These guys do them every day on LR/RR without lifting the body so why could you not work it out. I do agree a lot of modern cars will not be around as long as the earlier ones but that will be down to the advanced technology issues and getting replacement parts in later years. Now I like to spend my time on these forum sites helping out enthusiasts and hopefully save them some expense and give them confidence to at least have a try to fix things themselves.....having 'tit for tat' knowledge mind games on line in threads is not my scene as it spoils genuine information threads....as this was just in 'idle chatter' I have gone along a little but will move on now please. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2031 Registered: 9-2004 |
"These guys do them every day on LR/RR without lifting the body so why could you not work it out." Steve in reply I think you have not grasp the turbo replacement correctly. To replace the turbo without the EGR valves is bad news and will cost great expense after a short period. The heater plug replacement, try and get a quote from LR dealer!. They have not worked out a way doing a replacement on old units without the common problems ending in head removal in some cases. Needless to say we have. Yes time to move on. |
