ABS pump accumulator
 

Hi guys,
In and XJ6, this system has a working pressure of 83 to 100 bar. I need a simular system up to 170 bar (2500 psi). Is there a Jag using 170 bar (or higher then 100 bar)? It is also for an English car: Lotus Esprit S4, but these pumps are impossible to find, even 2e hand, and anyway I want a more relaible system :-) .
Many thanks (karl_lambrechts@live.com)

Hi Karl,

Welcome to the Jaguar Forums. I recently drove a late model Elise but I've always loved the Esprit!

I am not aware of a Jaguar that uses a hydraulic system running the kinds of pressures you need. If your brake system was made by Delco, you might do some research to see if it was used in any GM vehicles (including pickup trucks like the GMC/Chevy 2500/3500). Have you looked at Rolls Royce, Citroen, Hummer, late model Mustang V8s, large pickups like Dodge Rams with Cummins diesels or Ford Super Duty diesels? I believe many of those use hydro-boost brake systems, some with external accumulators and some with the accumulator integrated in the power piston. I don't know their max system pressures but maybe one of them would be suitable for your project.

Lotus is such a small-volume maker that it is unlikely the brake systems were custom made for Lotus - they may very well have been used on some higher-volume vehicles.

Cheers,

Don

ABS brake pump, accumulator and pressure switch
 

Hi Don, thanks for that info. I checked many, many systems. The combination motor+pump, pressure switch and accumulator is rare (however logical), and is not used anymore: today the priciple is slightly different (therefor pumps and accumulator can be much smaller), and it is nearly always with integrated electronic controller.
Lotus used the Delco Moraine system, nowadays ACDelco, and was reasonable succesfull in the years 1989-1992 (Buick, Chevy, Pontiac,...and Lotus - used it untill 1998 in the Esprit GT3). I searched around the world for a log time, but could only find 1, and it looked suspicious. (Most Lotus drivers just continue to drive with the failing pump -it is considered as fairly normal???, but it affects braking. The actual pump was made by Denso (Japan). Jaguar and range Rover used a similar system fom another manufacterer (Wabco). Range Rover uses 140-180 bar (very close to what I need) and in the mean time, I found (but i still need confirmation), that Jaguar also used 140-180 bar.
As far as I can judge today, I will go for the Range Rover pump, because it is more compact, and easy availability, (for little money). Of course unless Jaguer uses a higher pressure, which I hope :-)
Best regards
Karl

Hi Karl,

I'm sorry I don't know of a Jaguar that used hydraulic boost at such high pressures, but if you figure out that one did, please let us know for our mutual education.

One thing I should have mentioned is that many owners of the XJ40 have converted their original hydro-boost systems to standard vacuum boost using the booster from a Jaguar Series III XJ6. I don't know if you could possibly have room to fit a vacuum booster, but that might be another option.

Another possibility might be to find a hydraulic pump specialist who might be able to rebuild yours. We're very familiar with Denso and Wabco components on Jaguars - I would think that the commercial truck market might have used similar systems also. Maybe someone who services those systems could help?

Also, in my own research I've run across companies that rebuild accumulators for Rolls Royce and Citroen systems. Any chance one of those companies might be able to help with your pump?

I'd love to hear of any future developments!

Cheers,

Don

Hi Don,

I checked all the other names, but unfortunately, nothing will go.

But I found some remanufacterers for abs and brake pumps. There are not many:

1/ A1 cardone (USA): New, Remanufactured Auto Parts Leader | CARDONE
2/ Home (GB) | BBA Reman (UK)
3/ Technicentrum (France&Portugal) https://techniczentrum.com/fr/

This maybe also interesting: replacement pumps: Matt Sweeting's SPEED Manufacturing- Bosch Hydro-Boost, Bosch Hydro-Max, Vacuum, and Air/Hyrdaulic Power Brake Systems

I contacted them all, they all tell the same thing: send it by post, wewill analyse and there is a 80% chance we can fix, cost ca 75EUR for analysis, and if you do not want it repaired.

Cardone is far away, and expensive due to transport. Technicentrum looked to me as the most relaible.

Best regards
Karl

Hi Karl,

That sounds almost promising! Please keep us informed!

Cheers,

Don

Accumulator
 

Hi, are you talking about the 1987 system which uses hydraulics and a hidden accumulator or the 1990 system which has pretty conventional brakes but uses a small sealed accumulator and pump for boost.

Many modern cars use an accumulator system and when I was trying to find a replacement for my Soarer I looked at many different alternatives.

1. An equivalent unit and thread adapter, still not cheap but a good last resort.
2. Replace with a vacuum booster setup, better for simplicity and reliability but needs some engineering knowledge and may cause licensing or legal issues if not properly done with an engineering permit. I used to have a Silver Shadow that had all its high pressure hydraulics (2500 psi) removed and replaced with new lines and a Ford master cylinder and booster. Damn thing drove great and was no problem to register despite all the purists telling me it was impossible that it could work.
3. The Soarer booster could be opened up and have new seals fitted plus a Schrader valve for recharging, this is what I did in the end as it cost me $300 but can then be rebuilt and recharged as needed.

With my 1987 XJ40 I'm going to fabricate the bits needed to replace the overly complex booster system with a series 3 vacuum booster, but that isn't possible with the 1990 XJ40 and I'm sick of replacing the small spheres. On that car I'm going to use either a Citroen sphere from a Rolls Silver Spirit and adapter as these are cheap and easy to get but not rebuildable, an earlier Shadow sphere with adapter which is more expensive recond but fully rechargeable and rebuildable, or another make such as Toyota which is cheap and new enough to give me good service life and future replacement.
Both cars need to be re-registered anyway so legality issues can be dealt with properly.

Hope this gives you some ideas.