1988 735i use ATF or CHF 7.1?

[billleget]

I have a 1988 735i and the PS reservoir cap has sticker that says to use ATF but the Bentley manual says use CHF 7.1 with ATF used in later year cars being Dexron iii. What is the correct fluid to use? Thanks.

[youngbimmer]

ATF. My 88 735 calls for ATF on the reservoir so that’s what I feed it. The pentosin only needed if you have SLS

[billleget]

i have the self leveling suspension which is why i thought the cap should say to use CHF 7.1. Where's the best place to drain the system so the fluid can be replaced? thanks.

[billleget]

Build date is 10/87. Saw another post explaining how the H31 system worked that early cars used ATF and later ones used CHF 7.1 and still later ones used 11s. Can someone verify this?

[shogun]

Yes, 735 like your 10/87 with H31 hydraulic brake booster -and in your case anyway with SLS - uses Pentosin CHF 7.1, no longer available, but Febi Bilstein has replacement , Febi Bilstein Hydraulic Fluid 06162.
They also have substitute for Pentosin CHF11S, febi-bilstein 06161 full synthetic.
Pump the brake pedal about 20 times till the brake pedal get's hard, then the brake bomb is fully empty of Pentosin and the fluid is in the reservoir, such it out with a turkey buster, that is abt 50 % of all the system fluid already, fill it with the new fluid, run the engine a bit and turn the steering wheel, do the same procedure again, then most is gone of the old fluid, refill maybe later once more and repeat procedure. With this method you do not have to open any connection in engine bay or under the rear, which might leak later.
Here is a drawing if you want to drain somewhere else http://www.bimmerboard.com/members/s...mSchematic.jpg

[billleget]

thanks shogun for the info. i'd rather not break fittings if i don't have to so i'll feed and bleed as you suggested.

[shogun]

10/87 735i/iL has this brake system with H31 http://bmwfans.info/parts-catalog/E3...ke_servo_unit/
and your reservoir has a filter inside, see here http://bmwfans.info/parts-catalog/E3...e_singl_parts/
filter cartridge 32411128167 , costs abt. $20, you can disassemble the reservoir and clean this filter with brake cleaner and re-use it. some shops anyway already list it as NLA https://www.ecstuning.com/b-genuine-...r/32411128167/ but when you google with the p/n you can find some offers

[youngbimmer]

I did not know 735i can be equipped with SLS/LAD if it is not an iL model. I thought all basic 735i did not have the special suspension.

[shogun]

that was available as optional extra code 220 for the 730/5i M30, 730/40i V8 and standard for iL, German list prices show option 220 as: SLS/LAD for rear axle, , including larger fuel tank 102 Liter instead of standard 90 Ltr, delete of standard automatic headlight aim motors/system (as not necessary with LAD), 1993 the extra price was DM 1485,00 = EURO 759,27 = approx $800.
No extra price but included for 740iL, 750i, 750iL

[youngbimmer]

Very thankful then mine does not have LAD. It’s a true pain when it begins to fail plus you can only use the expensive pentosin or equivalent