In this video we will be replacing a power brake vacuum booster which has developed a very loud and noticeable vacuum leak on an old body style (OBS) GM truck. Such a leak is easily identified from the "hissing" air sound made during prolonged brake pedal activation, as well as from the random tachometer RPM flutter that will occur from the vacuum leak effect on the engine itself. While it is "normal" to hear a short and slight hiss whenever depressing the brake pedal initially on these OBS GMT400 trucks, this should not be loud and persist while stopped with the pedal fully depressed (though some remanufactured units lack a quality foam silencer so are not as quiet as original GM boosters were).

The truck illustrated is a 1998 Chevrolet Cheyenne K2500, but the procedure and replacement part will be the same for any 97 thru 00 OBS truck with a vacuum power brake booster option (RPOs JB5, JB6, JB7). Chevrolet, GMC, and Holden for Cheyenne, Silverado, Tahoe, Yukon, Suburban, Sierra, and W/T trucks across C1500, K1500, C2500, and K2500 ratings.

NOTE: Some remanufacturers of vacuum brake boosters do not replace all of the vacuum seals, so you can get a remanufactured booster that has a slight hiss out of the box as well. In these situations you just have to return the reman unit, and hope for a better rebuild in the replacement booster you get next. Such is the world of non-OEM aftermarket parts for these OBS trucks.

The eBay and Amazon search links below are paid links, for which I may be compensated and earn a commission, if you choose to buy the parts and tools shown in this video thru them:

Cardone 54-71085 remanufactured power brake vacuum booster (unloaded): https://ebay.us/gxk8eg or https://amzn.to/3uLzdgj (note: rebate link below Amazon price is for core return)

Cardone 5C-471085 brand new aftermarket power brake vacuum booster (unloaded): https://ebay.us/U5RIFW or https://amzn.to/3AqMuOP

Cardone 10-5000MCB brake fluid syringe: https://ebay.us/cfWV8a or https://amzn.to/3nAIHqv

LMC Truck 31-2305 power brake booster firewall gasket: https://www.lmctruck.com/1988-98-chev...

GM 15705042 brake pedal arm stud vacuum booster pushrod retaining clip: https://ebay.us/TzHkOl

GM 01470030 clamp for power brake vacuum hose to check valve: https://ebay.us/wTCHfZ

GM 11609949 nut (15mm nylon locking) for securing brake booster to firewall and master cylinder to brake booster: https://ebay.us/lnw6hk

ACDelco 14PB4064 / GM 19286764 remanufactured power brake vacuum booster (DISCONTINUED) superseded GM 18047682 (RPO code JB5/JB6 production sticker "DA") and GM 18047678 (RPO code JB7 - production sticker "XF"): https://ebay.us/EpwRIG or https://amzn.to/3nAPwbA

GM 15960241 power brake booster firewall gasket (DISCONTINUED): https://ebay.us/NkOtQt or https://amzn.to/3P3TMw8

GM C/K truck factory service manual: https://ebay.us/fRJN91

And if I've saved you some $$ here, consider some coins for the coffee tip-jar! https://ko-fi.com/drshock

1997 1998 1999 2000

Chapters:
0:00 - Problem overview
0:40 - Symptoms review
1:39 - Service manual procedure overview
3:40 - Preparing the master cylinder for removal
5:36 - Removing the master cylinder
8:18 - Disconnecting the brake booster vacuum line
9:51 - Locating the under dash fasteners
11:20 - Removing the brake booster pushrod retaining clip
16:52 - Removing the brake stoplight switch
17:37 - Removing four firewall retaining nuts
19:15 - Disconnecting the booster pushrod from the brake pedal stud
19:30 - Pushrod retaining clip inspection
20:08 - Tools used for under dash fastener removal
21:27 - Removing the brake vacuum booster from the vehicle
22:17 - Inspecting firewall gasket
22:36 - Brake booster replacement part identification
25:52 - Firewall booster gasket replacement information
26:57 - Installing the new vacuum brake booster
27:39 - Replacement retaining clip information
28:00 - Reconnecting the booster pushrod and stoplight switch
28:51 - Installing new retaining clip
30:40 - Reconnecting the vacuum hose to the booster
31:26 - Reinstalling the brake master cylinder

#drshock #obstruck #obstrucks

Disclaimer: DrShock, the alias for the human content creator for this YouTube channel, is not responsible for any damages, injuries, losses, or liabilities associated with any repairs, upgrades, or maintenance performed on yours, or any other, vehicle whatsoever. No warranty, express or implied, is made as to the accuracy or completeness of any information provided within this channel. Viewing and using the “as-is" information of this channel is totally at your own risk. Always wear personal protection equipment and follow appropriate vehicle manufacturer service manual guidelines with original manufacturer parts only when performing any repairs, upgrades, or maintenance upon any vehicle.