Quigley E350 Van: No brake booster! What is wrong?

[derjackistweg]

Dear all,

I recently had a major issue with my truck: Driving via autobahn roughly 25 km I came to the FIRST stop, was almost not able to get the truck to stop in front of a traffic light!
After a first shock and several km later I came to the conclusion that brakes still work but the brake booster is w/o function. afaik

I am no export and also no-one else here in Germany, but take a fortune!

Last year I did the drums in the rear (new pads, new brake cylinder, new line, new pad in the front, new master cylinder).
- Brake pedal is rockhard.
- Brake/emergency brake light are now on, permanently
- vacuum pump was done 2014 für 330$, here in Germany (now you know what I mean) + labor
- brake booster is original, I guess. Looked good last year, when I changed the master cylinder just to be sure.

So I need to import everything, takes time and costs money.

I unplugged the the hose coming from the Vacuum pump, while engine running. I sucked a bit while blocking with my finger. But just a barely bit.

- I assume Vacuum pump or booster can be defect to cause that? Right?
- What does that red brake light mean? I does not light up when emergency brake is on (although it should, I guess). Does that mean it measures if there is enough vacuum? It is a 1993 one with rear wheel ABS.
- I hope the ABS is not causing this problem. This RABS has no hydraulic block but a porpausining valve at the frame, afaik.

How can I distinguish what is wrong?

 

[derjackistweg]

btw:
brake performance is very poor, although with 35" tires/ 315/75-16. No blocking possible.
The rear drum on the right side is pretty close to not accepted by TÜV. Which is German control unit for cars/trucks. w/o that I can walk and my truck is not allowed to be driven on the street.
I do have the Dually rear brake cylinder still here- though blocking in the rear is not the best, but I am far from that. 700 to 250 kNM brake result, if I am correct.

 

[Scotty4]

Does the vacuum pump spin freely if you remove the belt? I just changed mine and it was wasy to spin by hand. New one was really stiff. 12.5 mbar on old VS 62 mbar.

 

[Big Bart]

Per scotty4 check that you have sufficient vacuum at the brake booster. When the vacuum pump stops working your brakes will not have boost from the brake booster. Your vacuum pump may be working but have a cracked or loose vacuum line preventing the system from building vacuum. By checking at the booster you will know if there is a vacuum issue. If the vacuum is good then likely your brake booster will need to be replaced.

 

[Cubey]

Sometimes boosters are the problem I'm sorry to say. Mine is now basically impossible to get. i probably bought the last one in the entire US for ~1985 models. Every parts seller is out of stock with no ETA on when it'll be back. RockAuto is the only possible way someone might get a rebuilt one, because they sell a Cardone rebuild service where you send in your old one to have them rebuild it. Better hope it doesn't get lost or damaged though or the extremely rare booster will be that much more rare. I should have probably kept the old one but I didn't think to, I returned it for the core charge. But it was in fact bad, since I had already replaced the vac pump and the master cylinder was new too. The new one fixed the problem.

 

[1mouse3]

If is the brake booster, you could try getting ahold of someone that dose rebuilds of them like cardone and inquire about getting just a rebuild kit to fix the one you have.

https://www.cardone.com/

 

[derjackistweg]

Per scotty4 check that you have sufficient vacuum at the brake booster. When the vacuum pump stops working your brakes will not have boost from the brake booster. Your vacuum pump may be working but have a cracked or loose vacuum line preventing the system from building vacuum. By checking at the booster you will know if there is a vacuum issue. If the vacuum is good then likely your brake booster will need to be replaced.

Right, thanks scotty.

the so called " sufficient vacuum" is the problem. I already did the so called finger-against-the-line-while-running test

I checked the service manual I bought last year for the 4 and a half Generation Vans, which only party covers our IDIs:
"
1. Turn key off, disconnect vacuum line and connect a vacuum gauge with a "T" fitting to lower part of dash mounted plastic check valve. See Fig. 9. Start engine and allow to run at idle until vacuum
reaches 17-21 in. Hg.
2. Turn ignition off and observe vacuum gauge for one minute. If vacuum drops more than one in. Hg, replace power brake booster check valve. If vacuum does not drop more than one in. Hg, go to next step.
3. Reconnect vacuum gauge in same point as in step 1, but leave rest of system connected. Start engine and allow engine to run at idle until vacuum reaches 17-21 in. Hg. Turn key off and observe vacuum gauge for one minute.
4. If vacuum drops more than one in. Hg, disconnect each component one at a time and repeat test procedures in step 3 until leaking component is found. Plug disconnected vacuum line while performing test procedures. Repair or replace defective component as required. On diesel engine
with dash mounted power brake booster, replace power brake booster check valve also. If vacuum does not drop more than one in. Hg, go to next step.
5. Start engine and run engine until vacuum reaches 17-21 in. Hg. Turn ignition off and push down
on brake pedal for a few seconds and release. If vacuum pressure drops to zero in. Hg, replace power brake booster. If vacuum pressure does not drop to zero in. Hg, system is okay. Remove vacuum gauge and reconnect all vacuum lines."

Not sure if this relates to IDI or DI and or these are different in that regard.

But I have no clue what kind of gauge I need and if that is cheaper than the pump itself...

Plus I need to check what the hell in HG means in our measurements...

 

[derjackistweg]

Anyone an idea what the red "brake" light in the dash can mean?

Obviously it can show low vacuum I suppose. But what else can that mean? Because it can/could also lead in a different direction maybe...

 

[tradergem]

What is the possibility of installing a hydroboost system to replace the vacuum booster?

 

[derjackistweg]

Next:
I will check the amount of vacuum from the pump. 17-21 whatever unit means 0,5-0,7 bar, which is quite a lot.
Here is a tool - my brain only runs on 6 cylinders @ the moment - does that work for this job?
vacuum tester
It is for bleeding brakes but I guess when I connect that to a line it should show vacuum... or am I wrong?

 

[derjackistweg]

I thought so too but it is not worth the effort.

There is a good chance that I will sell the Van this year for a new project (4x4 Van, better than Sportmobile Interior, Diesel, and 28 years old. After 30 Years cost reduce to less than 1/3 for 30 year old cars).

But for that the truck needs to be tipp top.

Beside I guess (hope I am correct) that Vacuum pump or booster is defect. a less than 100€ repair.

 

[1mouse3]

vacuum tester

That should do and the 17-21 would be the outer reading of that gauge, you can use that to test the booster its self since can creat the vacuum.

 

[Cubey]

This company claims to have my extremely rare (84-86 van only) booster in stock. They claim to be one of the largest rebuilders in the US: http://www.pwrbrake.com/

Shipping to/from Germany would be expensive but if that's your only option, it's better than nothing.

 

[mexicanjoe]

Your brake warning light will activate to advise you that you have insufficient vacuum.

 

[Big Bart]

That would work, its for creating vacuum (One use is bleeding brakes.), but it will also read vacuum to your point.

You can also look for something like this on Amazon.

Amazon.com: OTC 5613 Vacuum/Pressure Gauge Kit: Automotive

Buy OTC 5613 Vacuum/Pressure Gauge Kit: Fuel Pressure Testers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Amazon.com: Hromee Fuel Pump and Vacuum Tester Gauge, Carburetor Pressure Diagnostics Leakage Tool Kit: Automotive

Buy Hromee Fuel Pump and Vacuum Tester Gauge, Carburetor Pressure Diagnostics Leakage Tool Kit: Fuel Pressure Testers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

As mentioned above, many companies in the US can rebuild these. One I have used is below. Perhaps if you have someone in Germany that can rebuild them, you can order the parts from a supplier in the US and have them install. (Save shipping more weight and both ways.)

J&J Axle Supply
1311 E. Chestnut Ave #F
Santa Ana, CA 92701
1-714-667-5202
[email protected]